Well, I don't have answers to your questions, but so as not to add another thread to the mix, I'll add a few of my own questions.

1. Will the n900 work on the Sprint network?
2. Can it act as just a stand alone internet tablet, or does it need to be activated as a phone too in order to use it?

As for item's 3 and 4, I don't know the exact answer, but I can take a fair guess from previous experience. With #3, I'd say all would be open source AFAIK. As for #4, given the nazi like way the cellular companies protect their network and lock you in, I doubt you'll have any access short of unlocking the phone.