Gaim: One IM Client to rule them all

Gaim is an Instant Messages (IM) client that is compatible with most popular IM systems. Gaim allows the user to connect to different networks (AIM, MSN, Yahoo…) at the same time. It supports many traditional features, such as "buddy" notifications (log-in/out, busy…) and brings many specific features, such as the ability to run a program on a specific notification. Gaim runs on windows and Linux. Some PDAs are also supported. [FAQ]