Hello, I still have my old att simcard that I've had since before att turned to cingular. now that cingular is turning back into ATT will my old sim work with the new att phones?
Nope. The old ATT is branded differently. The new ATT is cingular with a name change. What you need to do is to upgrade to a cingular sim, which incidently have been upgraded to work better on 3g.
If you want to keep the old ATT plan then you will need to get an unlocked phone.