Palringo

Palringo is available for Windows and Mac (currently in testing) but its niche seems to be when used on a mobile handset like an iPhone or Blackberry.

For your existing contacts it supports Google Talk, AIM, Yahoo! Messenger, Windows Live!, etc. but also adds a dedicated Palringo account. This Palringo service has easy to add or join Groups providing office and small business users a convenient way to communicate.

A feature that might prove useful is voice and picture instant messages. Send a quick voice message to a co-worker.

Beejive has a somewhat similar IM client and Fring competes on the iPhone. Read more