Hiding a Process (Making a Backgrounded App)
Mac OS X Only

To hide an application process in OS X 10.2 and earlier, open the Info.plist file in the Contents folder of the application package. Add this to the <dict> section (it doesn't seem to matter where):
<key>NSBGOnly</key>
<string>1</string>			
In OS X 10.3 and later, add this instead:
<key>LSUIElement</key>
<string>1</string>			
Doing this will remove the process from the Dock, and from any menus that list active (visible) processes. To show it again, you can either put in a 0 instead of a 1 for the <key>, or you can remove the whole thing.

Cross-posted from the SuperCard List
Updated 8/25/04 by Ken Ray from a tip posted by Devin Asay to the Use-Revolution list