I found this website with great instructions for rooting the Atrix. I do not know if this works on all models of the Atrix.
Motorola Atrix – RootzWiki http://j.mp/wqlVfN
I hope it works out for you. Let us know if This root method works and what version firmware you tried it on. Also if you tried the unlock bootloader method too.
Drivers are located on the Motorola Website but here is a link:
Links may change so there is the Download Section on the Motorola Site:
USB and PC Charging Drivers – Motorola Mobility, Inc. USA http://j.mp/xoOLTh
To paste lines in the Command Prompt, you just have to right-click on the window title and navigate to Edit-Paste… That’s it! – Thanks to YouTube user ricksilverio for the info!