I am looking to sell my 3GS to save up for the 4g iPhone...can I just sell my iphone and put the sim in a old cingular phone I have and still keep the iphone plan on it until the new iphone comes out?
I dont see why not.
I dont think AT&T or any other company will automaticly remove a feature from your account to save you money.
They will just continue charging you untill you call to have it removed.
I don't understand why AT&T isn't truly investing that money into making their network better. I'll admit it's gotten somewhat tolerable over the past year.
But the dropped calls and lost 3G network in a totally "blue blanketed" area drive me insane.
You can try it, but it didn't work for me. Last week I had to switch my SIM card from my 3GS to my Motorola V3XX for only a day, and after I looked in my online account, I saw that AT&T removed the iPhone data plan from my line.