google messages

Free software to send free SMS (and MMS) messages from your Mac

Telephone on hold messages and music player software for Mac

Advanced Mac Mailer allows you to send out personalized bulk messages

Syncs SMS/MMS messages from Palm-based Treo smartphones to Mac.

Add cards in Address Book from selected Mail messages.

A plugin for Apple Mail that shows messages

It lets you send/receive messages instantly and participate in chats.

Automatically send e-mails, faxes or SMS text messages from FileMaker Server

Quickly send messages to your Adium contacts.

HTTP Client is a debugger tool for HTTP messages