[ROOT]NachoRoot - supporting all firmware jan 3rd 2012

[baseballfanz]

This is the latest root method, support all firmware so no need to downgrade firmware.

[Exclusive] 'NachoRoot' Brings Root Access To The Transformer Prime, Even With The Newest Firmware

You need to have ADB setup.
Good tutorial here
[GUIDE] Getting ADB Setup; An Idiots' proof guide on getting ADB working for Rooting! - xda-developers