Going to Japan for a few weeks. I'd like to take my Evo with me, I plan to use wifi while I'm there but my question is since my phone will be in a constant roaming state, will this reflect on my bill with a crazy charge for roaming? I don't plan to use the phone for calls; just only pictures and some app's when I'm in hotspots for access.
Set your phone to Sprint Network Only, ie. do not allow it to roam.
Also CDMA is mostly in parts of Tokyo (although I haven't been there for years), so you should not get a signal most of the time any ways.
I do think that if you keep the phone on, you will drain the battery fast, as the phone will keep searching for the Signal. Put it in plane mode or something.