I'm always, well, tickled by the things that can happen when you use Terminal commands that begin with "defaults write" -- thus changing the preferences for applications, the Finder, and more, often in ways that you can't accomplish via GUI pref settings. I also get a certain warmness from Leopard's Data Detectors, but I have to confess I rarely use them. It's fun to watch the things that Mail can pick up on, and I've often tested to see what exactly iCal will make of it, but I guess some people just get better emails than I do. Strangely, I do get dates and info via instant messaging on a more regular basis.
You can enable Data Detectors in iChat with one simple command in Terminal:
defaults write com.apple.iChat EnableDataDetectors 1
You can disable it using the same command, but change the '1' to a '0.' Now you get the fun job of calling your closest Mac-using relative and explaining Terminal so they can use a feature that Apple hid from public view for what I can only assume were valid reasons. I hope your aunt has her screen-sharing figured out.
[via Mac OS X Hints]