Most business travelers use the web for at least some portion of their trip--whether it's planning, booking or compulsively checking the Weather Channel. But the web can offer more to make life easier. Here are a few under-the-radar sites to note.

Remote file access. One of the toughest things about business travel isn't the travel part--although crummy flights, horrible hotels, surly service and bad food are trouble enough. No, the business part is often more difficult because you're away from your business support system, both the human and the automated kind.

That's why Box.net is so handy. Need a file, spreadsheet or document, but didn't download it to take with you? Maybe you didn't bring your laptop or you have a problem with it while you're on the road. Perhaps you have to make an impromptu presentation and need some backup. Box.net lets you store, access and share your files from any location (home, office, satellite office) and from any device, including iPhones and BlackBerry phones. Box.net's OpenBox Services include a clean, intuitive interface for editing, previewing, faxing and signing documents. And there's no software to download.

Itinerary management. You just began a multi-leg trip. You booked two flights on Orbitz, two on AA.com and two on jetBlue. You made all of your car rental reservations through Thrifty, booked a room for one night on Hilton.com and the rest of your accommodations on hotels.com--except for the night you're staying at a B&B, which you booked by phone. Keeping track of all of those confirmation numbers is a nightmare; so is figuring out how to get from place to place with the least amount of wear and tear. That's where TripIt comes in.

TripIt bills itself as an online travel assistant that organizes flight, hotel, rental car, train, restaurant and various activity reservations--even when booked through different online services and vendors. Forward each travel confirmation e-mail to plans@TripIt.com, and the software automatically builds a master online itinerary that combines all the bookings with trip details, confirmation numbers, a daily weather forecast at your destination(s), local maps, driving directions and city guides. You can even add notes about client meetings and access the details from any browser or mobile phone.

Itineraries instantly sync with business calendars, so you don't have to enter and update trip details manually. You can also share itineraries with colleagues, assistants and family. "Closeness" alerts notify travelers whenever their plans overlap with those of people they know who are on the road at the same time.

Web 2.0 advisor. Primarily focused on leisure travel but a boon to road warriors seeking peer advice, IgoUgo offers a goldmine of information from experienced travelers who weigh in on everything from hotel and restaurant finds to overpriced flea traps. The database of 4,100 destinations is also a great source of ideas on what to do (or not to do) at your destination when you have a lull in the action. A bonus: a travel deals section on hotels, airfares and, if you're so inclined, vacations.

Save your tush. Matthew Daimler created SeatGuru  in 2001. As a frequent traveler, he--as a hobby of sorts--started making interactive airplane seating charts to share with friends. That group of friends burgeoned to more than 10 million visitors, all grateful to Daimler for showing how to avoid seats near the lavatories, crammed alongside the bulkhead or facing backward. You'll see at a glance the roomiest seats in coach, the wings (If you hate turbulence, that's the best place to sit), the emergency exit rows, the galleys--and even where the power ports are located.

The site now features 400 airplane seat maps covering 55 airlines. A bonus: useful details about each airline, including whether additional fees apply for luggage, food, soft drinks pillows, etc.; the availability of on-board magazines; and the web addresses of frequent flyer programs.

Find a great gym. For travelers frustrated with overhyped hotel "health clubs" that are little more than converted guest rooms with a treadmill, a mirror and some dumbbells, Fit For Business  is for you. This online database of hotel fitness facilities and private gyms is influence-free--meaning that site owners don't get paid for listings. Type in your destination, and you'll learn what to expect in both fitness and business amenities, from the weight range of dumbbells or the type of squash court to the availability of two-line telephones and in-room fax machines in guest rooms.

Soon to come: integrating the information with Sweatime, the company's online scheduling and reservations system for athletic clubs. You'll be able to use it not only to find a place to work out, but also a racquetball partner, a personal trainer, a fitness class or a massage.