Imguana is a multi-protocol instant messenging client (similar to Gaim) for Windows. In the future, a Mac and/or Linux version may be released.
Iris MSN is an MSN framework based on modularity and the populair build tool Maven. IRIS MSN provides a full implementation of the MSNP8 protocol. Included is a simple example.
Open Source Community Software. With this software you can create profiles, chat with other people, visit other peoples profiles, create your own picture galery's, and later your friends will be able to watch them.