AT&T has announced it's brand new Passport international package that includes unlimited messaging, WiFi access at AT&T hotspots, reduced calling rates and a little bit of data. It's available in over 150 countries.
The packages range from $30-120 for a 30-day period, making them ideal for travelers who travel internationally only occasionally. The data included isn't anything substantial, just 120MB at the $30/month rate, or 800MB for $120 - but should be enough to check e-mail and do some very light browsing.
RVer's who cross into Canada and Mexico, or who travel internationally occasioanlly, might find these plans appealing as a way to get online and supplement WiFi access they might find in RV Parks and cafes. However, for extended international travels, it might still be best to seek out other options, which can be found in the International Travel chapter of The Mobile Internet Handbook.
For more information on the new plans: AT&T Passport Page