Actually, I've been furiously researching the issue for the last hour and have found that, with the newest firmware, its possible to get it working just fine with Cingular. It has to do with using a slightly different access point for internet (internet vs. wap AP) which will allow the phone to have two simultaneous connections active at the same time.
Until I get my e61 in the mail, I wont be able to verify although I'm quite confident.