If you're still using Panther for one reason or another but drool when you hear the word 'Spotlight,' an app by the name of Pocketlight can bring a little bit of Tiger to your Panther. Pocketlight isn't nearly as all-encompassing as Spotlight, but it can search Mail.app mailboxes, iCal events, Address Book contacts and files in a specified folder. In an odd turn of events, Pocketlight is only available for Mac OS X 10.3; not 10.4.
Pocketlight is free, but the author states that it isn't going to be updated or enhanced from here on out, so grab it while you can.
[via Hawk Wings]