will i be able to install & use AutoCAD (any version) on my netbook?
Since AutoCAD has been around since the 386 processor, I don't doubt there is a version you can use. You'll just need to workaround the OS-compatibility issues that are sure to arise.
AutoCAD isn't necessarily a 3D CAD program, one of it's features allows for 3D viewing, but generally I've (personally) always associated AutoCAD with Polylines and drafting, and other primarily 2-D tasks. when I think "3D program" I think of 3DS Max (which coincidentally is provided by the same company).
The only way to surely answer this question is to try it. Theorizing about what it can and cannot run and how it compares to other machines that other people have run the software on successfully get's us nowhere.