I know this isn't necessarily an Android question but since iDen is on the way out can these devices be used without a service plan as walkie talkies? I thought I read somewhere certain models can be used as walkie talkies as long as they're within range of each other? Is this correct or is it just a myth?
That information is correct. Nextel phones that support the Direct Talk feature (not all do) can be used as walkie talkies within a certain range (max: ~6-7 miles, probably more like 2-3 miles in real world usage) without having cellular service activated.