I was just wondering if I had to use a .Mac email account with Mobile me or if I could use my comcast.net email account with it? Also does it allow more then one email address at a time?
It definitely will not work. I don't think it would even be possible to create this. MobileMe would have to take over server-side actions on Comcast/Google's mail servers.
But you certainly can set your phone up to check both mailboxes.