I am profoundly ignorant of these things. If here is no 3G carrier, or I buy an N900 and don't sign on with a 3G carrier, could I still use the N900 as a phone (the way I use my current cell phone, a "shiny" samsung from virgin, I don't think it has a sim card in it) and as wifi internet tablet the way I use my N800? Would I just loose the "smartphone" 3Gness of the N900 (the internet while away from wifi)? Or do I misunderstand?

Pointers to information at elementary level explanations appreciated.