http://code.google.com/p/phpmsnclass/
MSN class for php, support MSNP9 (MSN 6.2) and MSNP15 (WLM 8.1), use as a bot or just send message to MSN or Yahoo (via MSN, you need Yahoo 8.1 to communicate with MSN). Support OIM (offline message) if using MSNP15.