RORO01 ONLY THE INCLUDED SOUND FILES ARE USEFUL.
The only use I found for this application was to move the sound files from it's "resources" folder to "/System/Library/Sounds" folder so that they will appear in all the applications which use system sounds, like iCal - before I trashed the application.
By the way, if you want Skype sounds to be used in the same way, copy the sound files in it's resources folder to your desktop, convert the copies to AIFF files using Switch application (freeware) and move the AIFF files to "/System/Library/Sounds" folder.
(Version 1.1.1)