Apple Magic Trackpad is an excellent state of art hardware. However, it was very difficult to use Apple Magic Trackpad properly in Windows 7 due to virtually non existent good driver program for Windows Operating System.
We have found a German geek, who has developed a nice .Net based application to use the Apple Magic Trackpad in Windows 7 rightly.

He has named it Apple Magic Trackpad Control Panel.
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It has a bug after hibernating Windows 7. It get fixed after restart.
The developer has written how to use the Apple Magic Trackpad software in Windows 7 in English in his blog here for easy understanding.

There is a free and convenient Windows driver installer for the Magic Trackpad available. In addition there is a Control Panel to configure touch and other settings for the Magic Trackpad under Windows. http://www.trackpadcontrol.com