I just bought an N73 from I Cell in San Francisco. Got it with a 1 year TMobile agreement. Phone was $250 ($275 with tax). If you go with a 2 year agreement with TMobile, it's less than $200.
Only downside was it took them 9 business days to get the phone and the guy signed me up on the spot, which disabled my Verizon account and would have left me stranded without a phone for a week if he didn't have a spare GSM phone to lend me.
Wait until the phone arrives to enable your account since you're currently on Sprint.
Additionally, the power connector for the charger is EU, so be sure to get a US charger from them (I still need to do this, I'm using a converter right now which is not ideal).
So far I like the phone, but it's still a phone WITH a camera, not a phone AND a camera. Meaning, if you're expecting digital camera quality pics and usage, it's not quite there yet.
I also got a 2GB miniSD card, which shows it as being able to hold 2700 pics when empty. I loaded it with 1.3GB of music which I can play from the file manager, but the media application has to scan for mp3 files and it takes forever. I haven't let it process enough to index the mp3s. I'll do this overnight sometime.
(btw, if you have any more questions, don't respond directly to me, this is not my account)