From Email Address: anyuser@comcast.net (must be a comcast username)
To Email Address: anyuser@anydomain
SMTP Server Address: smtp.comcast.net
SMTP Server Port: 25 (or 587 if 25 doesn't work)
Enable Authentication : Yes
Account Name: anyuser
Password: <typepasswordhere>
Verify Password: <typepasswordhere>
If that doesn't work, let me know. Have no way of testing it, on a different ISP. Details obtained from