Take command of your POP3 mail accounts
Best Mail.app friend. All you messages in menubar.
Collection of useful AppleScripts for Mail and Address Book
Forward your POP mail to any e-mail address
Mail Call is a full feature mail notifier for email accounts that support IMAP.
Safeguard your mails with easy to use Universal Mail Backup / Archiver / E-mail Viewer for Mac OS X
Incoming e-mail at a glance
Automatically sends a message when you're away
A Free Internet program for Mac
Create hyperlinks which point to specific e-mail messages