T was 1 a.m. and sunny when Ben Saunders, a young British adventurer, stumbled giddily into the mess tent at Camp Borneo, a way station for thrill seekers, scientists and extreme tourists 60 miles from the North Pole.

Sodden and chilled, he had just completed 13 solitary days of skiing, swimming and trudging to and from the top of the world, towing provisions and gear 120 miles in a sledge across the crack-laced ice floes.

Now that he was safe and warm, what was the first thing to do?

He did not join the French trekkers, South Korean skiers and Russian skydivers celebrating Russian Orthodox Easter with boiled eggs and rounds of vodka.

Instead, Mr. Saunders, 25, sat down at a table, pulled out his palm-size iPaq digital assistant, his pocket-size Global Positioning System locator, his satellite phone and his digital camera and began updating his Web site, http://www.northpole2003.com/.

Such is the state of exploration these days.

In the last four years, ever lighter electronics and a growing grid of world-girdling satellites, along with a network of programmers, tinkerers and trekkers, have brought real-time connectedness to the world's most remote places. "G.P.S. and satellite phones have kind of revolutionized the whole thing," Mr. Saunders said.

Some technology is used as it comes off the shelf, while some is customized in an endless quest for the best performance at the lightest weight, said Tom Sjogren, a co-owner of Explorersweb, a Manhattan-based company supplying software, hardware and a home on the Internet to Mr. Saunders and others at the world's last frontiers (http://www.explorersweb.com/).

When a trekker must drag or carry everything needed for, say, a two-month trek to the Pole, every ounce counts. Each additional pound of gear supplants a pound of food, about half a day's rations.

Mr. Sjogren and his wife and business partner, Tina, both 43, have a toilet-paper distributorship in their home country, Sweden, but got into the trek technology business as they ventured to both poles and up Mount Everest and other daunting peaks. They longed to share each step, both virtually through constantly updated Web pages and by devising specialized communications gear, he said.

But conventional laptops were too heavy, hand-held organizers were incompatible with satellite phones, and batteries of all kinds faltered in the polar deep freeze. They enlisted programmers and engineers around the world to force devices to talk to one another, then tested them by taking them on extreme ski treks and climbs.

Sometimes the solutions are simple, Mr. Sjogren said. For instance, custom-built holders generating 12 volts from batches of AA Energizer lithium batteries proved superior to every other type of power storage. Others have involved elaborate combinations of custom-made software and jury-rigged cables and connectors.

Ms. Sjogren said their expeditions have been followed, minute to minute, by students, by a family in California who built a mock Everest base camp in the basement, and by cancer patients. "They're battling their own battles, and can tune in on our troubles, doubts, and fears while they in turn inspire us," she said.

Mr. Saunders is among the Sjogrens' customers, using a custom-designed communications kit - a yellow weatherproof box of gear can cost around $3,000, or can be rented - and relying on their Web sites as well as his to post daily logs. He and dozens of other adventurers now routinely use the Internet to promote their exploits and the products of sponsors that provide gear and financial backing.

It has become something of a competition to see who can transmit the most information and imagery the most quickly, with an intense race, for example, unfolding in recent days on the flanks of Mount Everest, where Chinese and American video crews vied to be the first to broadcast live television from the summit. The Chinese won.

The technology itself has also greatly increased the number of expeditions to the world's farthest reaches.

Indeed, Camp Borneo, which is built on the ice each spring by Russian and French entrepreneurs mainly to serve wealthy tourists, probably would not be attracting its annual complement of about 200 visitors a year without such technology.

Pilots flying from Siberia or Norway with the latest batch of ski trekkers or Champagne-toting tourists know precisely where the drifting camp and ice-carved airstrip sit because of constant telephone updates of G.P.S. coordinates from the camp manager.

The advent of simple, relatively cheap satellite telephones (calls cost about $1 a minute) permits nervous newcomers the remarkable indulgence of being able, with a few touch-tones, to chat with a relative while at the Pole.

Still, each of Earth's harshest spots offers special constraints. The towering Himalayas preclude the use of the most popular telephone system, Iridium, which relies on satellites in orbits that are easily blocked by the soaring peaks.

But climbers there can now stay in touch by using Thuraya, a new telephone system that links users through a satellite in an orbit that is synchronized with the earth's rotation, so it is always over Asia.

Since it is all ocean, the North Pole has no hills to get in the way of Iridium signals, but the shifting ice means that visitors had better be prepared to get their gear wet. And the sub-zero cold in March and April - the only time there is light but the ice is not yet breaking up under the summer sun - quickly drains batteries and freezes liquid-crystal displays.

Even G.P.S. becomes virtually useless right at the pole, where all longitudes converge. A single step can take one from the longitude of, say, Paris, to that of Honolulu.

Still, the advent of packages of software and hardware adapted to these extremes has eased the way for a substantial expansion of extreme trekking.

Knowing your location and being able to communicate are just the basics. Contact 2.0, the software developed by the Sjogrens, allows Mr. Saunders and others like him, whether on floating ice or the flanks of Everest, to send images, video clips and text directly to their Web pages. There is no need for a Webmaster or other intermediary to receive an e-mail message or attachment.

The Sjogrens said the need for this kind of automation became apparent during a recent Everest expedition when their Webmaster went on vacation just as they were approaching the summit.

While getting to know Everest in the late 1990's, they had also noted that the companies leading the big professional expeditions did not share weather forecasts with small groups like theirs, Ms. Sjogren said.

Now, Explorersweb provides text-message alerts to climbers' satellite phones, using precise Himalayas forecasts supplied by the Swedish government and a private forecasting service.

On Everest and in Antarctica, the Sjogrens have experimented with wireless systems that could eventually allow individual climbers to transmit images and their positions to a base camp and then onto the Web.

Mr. Sjogren said the Defense Department and firefighting groups were tracking their work with the idea that such methods might be adapted to reduce accidental troop casualties or to track emergency workers in buildings or in dense smoke.

Other options allow the outside world to track a trekker's movements. An explorer might, for example, take along a small transmitter like those used to monitor the migrations of rare wildlife, from elephant seals off Patagonia to the reclusive forest elephants of the Congo basin.

A French company, CLS, uses satellite networks to monitor the position and condition of explorers carrying the device. The version used by adventurers can send 10 different signals and, with prearranged codes, alert a support team to changing conditions.

Pen Hadow, a veteran Arctic guide and mentor to Mr. Saunders, had such a transmitter with him when a small airplane plucked him from the rapidly warming and cracking North Pole ice on May 27.

Mr. Hadow had finished what apparently was the first solo unaided trek from North America to the Pole but had then been stranded there for more than a week, his rations dwindling as foul weather prevented any flying.

Long after the last battery for his Iridium telephone died, satellites could still pinpoint his position every 20 minutes, and he was able to continue sending coded messages indicating his condition.

The last code he sent was the number 5, which - in understated British fashion - encouraged his support team to prevent him from starving by conveying simply that he was "contemplating resupply."

Even with the best technology, though, life at the planet's edges will not lose its hazards anytime soon.

Although Mr. Hadow's drifting position was known and satellite images on government Web sites provided frequent updates on storm fronts and ice cracks, the plane could not land to retrieve him until dense polar clouds slowly moved on.