Zoom Lens

Hey Guys!!!

I am sure u can solve this pblm. Ok..this is what i want...
I want to create a Lens application which can zoom my desktop. This what it should be. When the user double clicks my application..it should show a lens (u know a form in the shape of a lens) then he clicks on the desktop..it should zoom the whole desktop...but respective to the area where i click..there can be a limit for zooming...there should an option for PAN. like u have another form with 4 arrows on it...u click on the arrow and u scroll in that direction...if u know Microsoft Mappoint then u know what I mean..