free email client software

Exchange-compatible email client.

Portable Thunderbird OS X is the popular Mozilla Thunderbird email client.

Waveboard is a client software for Google Wave

A beautifully designed and very functional Twitter Client

Syrinx is a fully customizable twitter client designed for Leopard (OS X 10.5+).

S3 Browser is a free client interface for Amazon S3 Service.

Subversion client.

Create and send great looking email campaigns.