Keyhelper also alows you set up menus that can be brought up by key-combos that allow you to select an app or action to run - examples include starting apps, opening text editor with a specific file, closing down or suspending the Z, open dictionary and lookup selected word.
Basically if you can think of it, then keyhelper can probably do it. - along with being able to remap your keys.
Stu
p.s. I\'ve started and intro to keyhelper in the howto section that gives you the basics of keyhelper - more to come soonish