Ziplight Spotlight Plugin for zip archives
If you're a chronic zip archive user, this Spotlight plugin is for you: as its title suggests, the Ziplight Spotlight Plugin from Bartas Technologies allows you to search files inside of zip archives with the power of Mac OS X Tiger's Spotlight engine.
Installation is a snap, but the plugin does have its limitations. While Ziplight will allow Spotlight to search the contents of zip archives, it can't go one level deeper and search the contents of those files; doing so would probably bring Spotlight to its knees.
However, if you're tired of unarchiving zip files just so Spotlight can peek inside, head on over to Bartas Technologies to eliminate one more double-click from your daily computing.