What I'm trying to accomplish is to have an app which will accept VOIP calls open and running at all times so that I don't use cell phone minutes while I'm on WiFi. That was the joy of the Blackberry (also ATT): Whenever I was on Wifi, anyone who phoned my normal cell phone number was automatically routed through Wifi and connected to my blackberry, just like a normal cell voice call...but it was using VOIP and I didn't have to use my cell minutes. I was completely dumfounded to learn that this wasn't standard operating procedure for the iPhone. So I figured, OK, the next best thing would be to have the iPhone have Skype running in the background so folks could at LEAST contact me that way without it using my cell minutes.
So far, not so impressed with way ATT and Apple have this arrangement going. I hope I can find some Apps for the iPhone that impress me perhaps that will help redeam the (pretty lacking) VOIP integration that I've seen so far.
But I totally admit: I'm new at the iphone (Apple user since 84) and I may yet become convinced that this is a decent product.... Week 1 with the 3Gs, pretty disappointing.