Do you tether with your smartphone? I find that many people use smartphones and also carry laptops when they're traveling for business. Very few of these individuals realize that they can use their smartphone as a 3G wireless modem for their laptops. Tethering is a cost-effective way to stay connected if you don't want to pay for a dedicated 3G wireless card for your laptop.
My Thinkpad has built-in WWAN from AT&T, but I choose to tether using my smartphone since I can't justify the costs associated with paying for a dedicated wireless connection.
Tethering may not be available on the AT&T iPhone (unless you do some jailbreaking and hacking), but it can be done on Windows Mobile, Android, BlackBerry, and others.