Apple describes it this way:

"A bundle is basically a directory that contains an application. Unlike normal folders, however, it appears to the user like an ordinary file. The user can double-click a bundle, and the application will launch. Since the bundle is really a directory, it can contain all the support files that are needed for the application."

http://developer.apple.com/documenta...section_2.html

It would be great to have the functionality described in KDE, so please vote.