I have plans to create a simple bot for a game I run and have it sit on MSN and answer queries. I want to use Python to do this and googled around and found MSNP. I thought
You can use msnlib, which after a quick test seems to be up to date, and is quite a small and readable library in two files, with a reference implementation of a few cli chat clients and chat bots.
If you're prepared to do some hard work with the original source code, you could update it to support the current version of the MSN protocol:
http://msnpiki.msnfanatic.com/index.php/Main_Page
I don't know of anything equivalent, but you can look at the source to libpurple and roll your own without a terrible amount of difficulty.