I have all my Mail stored on my computer in one Comcast account and I was wondering how do I move it all to another Comcast account. Is the only way to forward it or can I just transfer it on my hard drive.
If I re-read that right, it sounds like you just want to change the email address associated with Mail.app? If so, your old messages shouldn't go anywhere. Heck you could configure both as two POP accounts if you wanted.