Rooted my Motorola Atrix

System version: 4.5.91
Android Version: 2.3.4

Instructions found below:

http://www.digitaltweaker.com/android/phones/2011/07/root-motorola-atrix-4-5-91-on-gingerbread-2-3-4/

If you get the "device not found" error when running "adb shell" then make sure you have sync drivers installed. When you connect Atrix to your computer the first time it installs a bunch of drivers and also gives an option to install "synch drivers". Make sure to install the "sync drivers".