Travis Feirtag shows how to
use an accelerometer and .Net 2.0 in 2D and 3D. To do the rendering, Travis uses GDI+ for the 2D example and Direct X for the 3D example. For an accelerometer, Travis uses the
Analog Devices XL202 Evaluation Board with an RS232 interface.
If you have the Xbox 360 Guitar Hero controller, you can use XInput to actually mount it as a controller exactly like an Xbox 360 USB controller.
Frets on Fire already has it working with a quick control map.