Save all your instant messages with IM history
This application saves your IM history across multiple computers and heck even multiple operating systems. IM History currently works with AIM, Yahoo, MSN, Skype, Trllian, and a few others. Using their web interface, IM History users can easily pull up their archived messages.
Think about the usefulness of this utility. Remember way back when one of your IM buddies gave you a link you're dying to get access to, weeks later? By using a tool like IM History, you can easily pull it up and be on your way.