International travel is enough of a hassle without having to worry about insanely high roaming charges, which is exactly what you'll pay if you try to check e-mail, use maps, or pull down some Web pages.
A new service called Doodad aims to minimize the hassles and expense of international data. The company sells prepaid SIM cards you can pop into your smartphone or tablet for flat-rate data access in any of 54 countries.
What's the catch? The SIM (mini or micro, your choice--nano is coming soon) requires an unlocked device, which might prove more complicated owing to the idiotic phone unlocking ban that went into effect in January. Best bet: ask your carrier if they'll do it for you. AT&T and T-Mobile reportedly will if you're an existing customer and your device is out of contract.
Alternately, a little Web searching will reveal lots of services that will sell you unlock codes, usually for under $10. (I recently used one to unlock an iPhone 4, and it worked perfectly.)
Once you've unlocked your device, order your Doodad SIM and add money to your account. Rates vary from 30 cents per megabyte in countries like the U.S. and Australia to as much as $1.20/MB in Bermuda, India and Jamaica. You've got 365 days to use your credit before it expires, and Doodad lets you set daily caps on your usage so you don't inadvertently blow through it.
Now, any seasoned overseas traveler will tell you that you can score local SIM cards and lower rates for less (meaning you buy one when you get to whatever country you're visiting). But that requires you to find a shop that sells them and cope with possible language barriers. (You could use Google Maps and Google Translate to overcome both obstacles--but only if you have Internet access. Irony!)
I should also note that Doodad's SIM works exclusively for data. You can make calls, but only with a voice-over-IP app like Skype or Google Voice.
Though it may not be the absolute cheapest option for international data roaming, Doodad looks to be one of the easiest.