can client

Gnutella P2P client.

MSN chat client.

IRC chat client from UNIX port.

A Groupwise client.

Enterprise-class open source mail/calendaring client.

Twucket is a new Twitter client for Mac OS X Leopard.

Jabber/XMPP chat client.

LoudHush is an Asterisk PBX IAX client.

A new open-source mail client for Mac OS X.

Clutch is a WebUI for the Transmission BitTorrent client