All major wireless operators available in the U.S. offer some international roam, but the volume varies by network. To get an understanding of how your network will fare abroad, or to understand which carrier to choose if you're a regular traveler, you should first understand the two basic major technologies that wireless operators use.

GSM (global system for mobile communications) is a technology used not only in the U.S. but in much of the world, especially in Europe. By consequence, carriers using GSM have a relatively large global network. The other major technology, CDMA (code division multiple access), has a much smaller network, with most of its popularity based in the U.S.

So, what does this mean for you? Major U.S. carriers AT&T and T-Mobile both use GSM, and both names have roaming contracts with over 190 countries. The U.S.'s T-Mobile is even owned by a German company that operates T-Mobile service in several European countries including the U.K. and the Netherlands. Therefore, phones serviced by AT&T and T-Mobile are more likely to be accessible during travel.

Meanwhile, Sprint PCS and Verizon, the U.S.'s most popular operator, rely on CDMA, making phones serviced by these operators less likely to work abroad. However, your carrier is not the only factor in whether your phone will work during your travels.

Even GSM-serviced phones are limited abroad due to the use of different frequency bands to transmit GSM signals in different countries. However, if you're a regular traveler, fear not: phones that can receive a variety of frequency bands are made to prevent this from being a problem. Triband phones, which receive GSM signals in 900, 1800, and 1900 MHz, and quadband phones, which receive those frequency bands as well as 850 MHz, are available, and are more likely to work in a variety of countries.

Those committed to CDMA networks also have options if they wish to use their phones abroad. CDMA carriers offer world phones for purchase, which have both GSM and CDMA radios and may therefore be used in a range of countries. Additionally, Verizon offers a Global Travel Program in which customers can rent a world phone for relatively brief trips to countries not serviced by CDMA, and even use their own phone numbers and voicemails. Verizon customers opting for this plan should also sign up for special international plans or prepare to pay regular international rates.

Now that you know more about where your phone will work, or which phones and carriers to seek if you travel often, you should consider the cost of using your phone abroad. AT&T and Verizon offer international plans which you can opt into for the month(s) in which you plan to travel.

AT&T's World Traveler plan, which costs a flat rate of $5.99 per month, affords subscribers discounts on international roaming. Verizon's international plan, which sets subscribers back $4.99 per month, discounts calls abroad. If you opt for one of these plans on your travels, be sure that the plan is in effect before you leave the country, and visit your carrier's website to look at their international roaming information and the cost of texts abroad.

Sprint Nextel and T-Mobile customers have less luck in this department; Sprint Nextel only offers a $2.99 plan that discounts calls in Canada, and T-Mobile has no plans that provide international discounts. If you plan to use a phone on either of these carriers abroad you should also be sure to view their international roaming, texting, and calling information on their websites.

While savings on texts and calls are valuable, what really racks up a phone bill abroad is data. AT&T offers 20MB of data in any of 65 countries for $24.99 per month, Verizon offers email and data access for upwards of $69.99, and no other carriers offer special discounts specific for international data use. In short, data is expensive. Look up your carrier's international data charges before leaving and plan accordingly. The best way to save abroad is simply to forgo data usage. Be sure to turn off data roaming to avoid sneaky (and steep) data charges!

If you really need access abroad, a helpful trick is to purchase a local SIM card. SIM cards can be purchased at most airports and are relatively inexpensive, and you will incur much lower expenses abroad with a local SIM card than you will using your own. If you aren't interested in paying in any capacity for data abroad, use a device like a laptop to stay connected via WiFi when possible.

Traveling will always cost a little money, but phone bills that look more like college tuition are entirely avoidable. Stay informed and plan ahead, and you can enjoy your trip without stressing about huge payments down the line.

About the Author -
Sharon Housley is the VP of Marketing for NotePage, Inc. a software company for communication software solutions. http://www.notepage.net