If you have a dual screen on a Mac, then there might arise situations where the apparent lack of a second menu bar on the screen is a bit limiting. There is a freeware option from a wonderful programmer Andreas Hegenber, a German developer studying for his masters at Technische Universität München, Germany
This application is called SecondBar and can be downloaded for free from ( http://blog.boastr.net/?page_id=79 ) this displays a second menu bar on the secondary screen. Combine this with Air Display running on an iPad and you have a complete second touch screen mac system.
The author warns that this is still in beta stage so use at your own risk, the app seems to be quite stable on OSX 10.6.6
The Author also has some other tools for the mac, like BetterSnapTool which allows you to snap the windows like with the Aero interface on Windows 7.
Another offering is the BetterTouchTool which allows for gestures/shortcuts to be created for use with the Trackpad, Magic Mouse, keyboard and a normal mouse. This app does not play well with Parallels and makes it quite clear upfront, understandable as Parallels does some nifty stuff in capturing and releasing the keyboard and mouse in the guest OS.
All these are free and are great tools for use. You can download them for use and also if you wish to thank the author, you can send him an email on bettertouchtool [a t] boastr.net and thank him for the lovely tools.