All kinds of IRC bots has existed for quite some time, everything from quiz bots to channel admin bots. You can't connect to IRC without seeing them. In the later years MSN Messenger has become increasingly popular, and now bots are beginning to appear here too.

I friend of mine, Frank Robert Kvam, has written one such bot, MSN-Hjelper (MSN Helper in English). MSN Helper can help you with some different things:

• Searching with google
• Looking up a number in the Norwegian telephone catalog
• Remind you of TV programs
• Calculator
• Wikipedia lookup

His wrote his bot using the free open-source class library DotMSN (http://www.xihsolutions.net/dotmsn/), which is a .NET wrapper around the MSN Messenger protocol. It is quite straight-forward to use, and only your own fantasy sets limitations for what kinds of messenger robots you can create

Add his bot to your contact list: msn-hjelper@hotmail.com 
Below is a screen shot of a conversation with it.