I'm switching to an AT&T Nexus One (back up advice)

[jd914]

I'm an AT&T customer currently with an unlocked Tmobile N1. Tomorrow I'll be switching devices and want to know if there's a way to back up my TMobile device and restore that data on my new AT&T device? Having had iPhones and Blackberries this was possible and one didn't lose anything data when switching devices and want to know if this is possible on Andriod phones. TIA