This is handy - 10.5: Compress a file or folder via drag and drop to Dock

nspired by this hint about the Screen Sharing application in /System » Library » CoreServices, I found another small but very nice application there.

Drag Archive Utility to your Dock (or toolbar or sidebar). Now, you can drag a folder onto the application, the result of which will be a compressed archive in the same location. If you don't like the default .cpgz format but prefer ZIP, or want to have another destination for all archives, just open the utility and change its Preferences.