Currently Being ModeratedJun 9, 2013 10:26 AM (in response to Gary - former developer)
First you got to find it.
Right click on Arduino.app pick "show package contents".
Application are made up of a bunch of folders.
Double click on Contents.
Double click on Info.plist. This brings up the plist editor.
If not or you do not like the plist editor, Download textwrangler.
Place textwrangler on the dock. drag Info.plist to the textwrangle icon. Edit.