SMTP Authentication

Almost all modern email programs support SMTP authentication - here is a list of the most popular ones which do:

Outlook
Outlook Express
Entourage
MAC OSX Mail
Netscape
PegasusMail
The Bat
Thunderbird

Please note if your email program is not listed it doesn't mean that it doesn't support this feature (please check within the program Help files for details). In some cases only certain versions may have this feature.