One thing that has always annoyed me in OS X is that the Empty Trash shortcut only works in Finder, so I wrote an AppleScript that lets you empty the trash from any application. First you'll need to download Spark. Make sure the Spark daemon is running and that 'Start Spark Daemon at Login' is checked in the General tab of the Preferences window. Once you have it set up, hit Command-1 to create a new AppleScript shortcut. Copy and paste this code into the window that comes up:
The showWarning property tells the script whether or not to show the confirmation dialog when you empty the trash. If it's set to true then you'll get the standard warning, and after you hit OK or Cancel, you'll be taken back to whatever app you were in. If it's false, then the trash will just empty itself in the background.Mac OS X Hints
http://hints.macworld.com/article.php?story=20090909014630766