Has anyone else done this?

I am a noob to the iphone world. I tried my att sim from previous phone and it works.

Any probs with that?
Will I have any extra charges or is that a stupid question?

thanks

No problems. In fact, you will get the voicemail notifications that non-ATT users did not get till they upgraded to 1.1.2

Make sure you have an ATT data plan though- the EDGE data adds up very fast.

Don't call up AT&T customer service from your iPhone. They will know your phone from its IMEI id.

Like I said i am new at this, so this might sound stupid:

If I don't enable the EDGE then I don't have to worry about it right??

One more thing. Can I put any other AT&T sim in without doing anything else like re-downgrading?

thanks for your help