Sean is traveling out of the country and had his iPhone unlocked by AT&T. He's concerned because it doesn't really say it's unlocked. Leo says he can go to T-Mobile and tell them he's thinking of going with T-Mobile and if he could pop a SIM in to see if it works (TMobile will let users bring their own phone to the party).
Should he get a local SIM in Europe, though? Leo says that's a good idea. It's far cheaper and he'll get a local number. The real key with buying a local SIM is to make sure it works in all the countries he'd be traveling to.
The other option is to get an International Data Roaming plan from AT&T, but it's expensive and he won't get a lot of data. He should turn off data roaming, because if he doesn't, he'll have a bill when he gets back in the thousands! Turn off automatic email and iCloud sync too, and look for McDonalds and Starbucks for free WiFi. Leo also suggests that he clears his usage stats when he leaves the country so he can monitor how much data he's using.
What about maps and directions? Leo recommends Motion X GPS, which will allow him to download local maps to his phone and then get offline. The Chatroom suggests OffMaps 2.
From the Chatroom -- Congstar 9 Euros for unlimited data in Berlin, Mobile Vikings 25 Euros.