Scanhill is a Microsoft Messenger Protocol Sniffer. Currently it can only intercept Instant Text Messaging. Given that mySQL is used, stored instant messages can be read through a browser interface that is written in PHP language.
imsniff is a pcap-based instantmessaging sniffer. It captures the IM traffic in the network and is able to log conversations, contact lists, profile information, incoming email notifications, other MSN events, etc. Tested in Linux and Windows.