PSI

Lot of instant messaging clients have been appearing lately, with this application being one such example.

PSI is a free IM application for Windows and Mac that lets you talk with your messenger contacts in a way that's simple and quick. It consumes hardly any resources and has a design that's both straightforward and stylish.

It's based on Jabber, which means you can talk with any contact who has an account with this open protocol, like Gmail users, for example.

You can also add other contacts from networks like Windows Live thanks to its transfer support. This makes PSI a great application that you'll definitely enjoy trying out.