Most IMers use AIM. But if you have a Hotmail account you have an MSN Messenger identity, and if you use Yahoo! Mail you have a sign-on for Yahoo! Messenger. Chances are, you have friends or coworkers on one of these—maybe also ICQ or IRC to boot. Multinetwork instant messengers let you sign on to any or all of these at the same time, in the same interface, maybe even in a better application than the native client.

Open-source Gaim 0.61 (AIM) (MSN) (Yahoo!) (free) is a great choice. Like many popular open-source applications, Gaim benefits from an active programming community. It has a straightforward, accessible, configurable interface. Setup is easy; you tell Gaim your log-on information and it takes care of the rest.

We found little to choose from between Gaim and Trillian, but some may prefer Gaim's simpler interface and its ability to run on Linux, BSD, and Mac OS X. One unique perk: Gaim has an unobtrusive spell-checker that highlights suspected misspellings as you type.