Generally, hotel surcharges on long-distance and local calls are astronomical, so you're better off using your cellphone or a public pay telephone. Most long-distance and international calls can be dialed directly from any phone. For calls within the United States and to Canada, dial 1 followed by the area code and the seven-digit number. For other international calls, dial 011 followed by the country code, the city code, and the number you are calling.
Calls to area codes 800, 888, 877, and 866 are toll-free. However, calls to area codes 700 and 900 (chat lines, bulletin boards, "dating" services, and so on) can be very expensive -- usually a charge of 95¢ to $3 or more per minute, and they sometimes have minimum charges that can run as high as $15 or more.
For reversed-charge or collect calls, and for person-to-person calls, dial the number 0 and then the area code and number; an operator will come on the line, and you should specify whether you are calling collect, person-to-person, or both. If your operator-assisted call is international, ask for the overseas operator.
For local directory assistance ("information"), dial 411; for long-distance information, dial 1, then the appropriate area code and 555-1212.
Just because your cellphone works at home doesn't mean it'll work everywhere in the U.S. (thanks to our nation's fragmented cellphone system). It's a good bet that your phone will work in major cities, but take a look at your wireless company's coverage map on its website before heading out; T-Mobile, Sprint, and Nextel are particularly weak in rural areas. If you need to stay in touch at a destination where you know your phone won't work, rent a phone that does from InTouch USA (tel. 800/872-7626; www.intouchglobal.com) or a rental-car location, but beware: You'll pay $1 a minute or more for airtime.
If you're venturing deep into national parks, you may want to consider renting a satellite phone ("satphone"). It's different from a cellphone in that it connects to satellites rather than ground-based towers. Unfortunately, you'll pay at least $2 per minute to use the phone, and it works only where you can see the horizon (that is, usually not indoors). In North America, you can rent Iridium satellite phones from RoadPost (www.roadpost.com; tel. 888/290-1606 or 905/272-5665). InTouch USA offers a wider range of satphones but at higher rates.
If you're not from the U.S., you'll be appalled at the poor reach of the GSM (Global System for Mobile Communications) wireless network, which is used by much of the rest of the world. Your phone will probably work in most major U.S. cities; it definitely won't work in many rural areas. To see where GSM phones work in the U.S., check out www.t-mobile.com/coverage. And you may or may not be able to send SMS (text messaging) home.
Voice Over Internet Protocol (VoIP)
If you have Web access while traveling, consider a broadband-based telephone service (in technical terms, Voice over Internet protocol, or VoIP) such as Skype (www.skype.com) or Vonage (www.vonage.com), which allow you to make free international calls from your laptop or in a cybercafe. Neither service requires the people you're calling to also have that service (though there are fees if they do not). Check the websites for details.
Internet & E-Mail
With Your Own Computer -- To find public Wi-Fi hot spots at your destination, go to www.jiwire.com; its Hotspot Finder holds the world's largest directory of public wireless hot spots.
Without Your Own Computer -- Most major airports have Internet kiosks that provide basic Web access for a per-minute fee that's usually higher than cybercafe prices. Check out copy shops like Kinko's (FedEx Kinko's), which offers computer stations with fully loaded software (as well as Wi-Fi).
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.