Okay so I'm getting the new iPhone 3G on July 11th whenever it comes out. But right now I have T-Mobile so I have to switch to ATT before then.

So how much, in all will it cost for the new 3G iPhone (idk if i want the 8gb or 16gb yet), the AT&T activation and the cheapest bill monthly (but i have to have unlimited text, the minutes don't really matter)?

Also, my T-Mobile bill is up in August but I want the iPhone when it comes out on July 11, so what if I just stopped paying my T-Mobile bill?