Earlier today at the World Wide Developer Conference Apple announced that the iPhone 3GS could be used as a tethered modem from 22 carriers.  However, at the time AT&T was not in the mix.

Later an AT&T spokesman, Mark Siegel said, "We will be offering a tethering plan and MMS for the iPhone. But we haven't announced a date."

Another AT&T spokesman Seth Bloom said, "we plan to offer a tethering plan but we don't have anything to announce today."

Boy Genius reports that the MMS will be late this summer because the code has to be changed manually on each iPhone 3GS.  He also hints that a tethering plan will be around $70 a month.

AT&T is accepting pre-orders for the iPhone 3GS. Orders placed online will ship directly to an address while orders made in a store will be available for pick-up on or after June 19.