Disclaimer: DroidForums.net or myself is not responsible if you break your phone while using this method to root your Bionic. Please proceed at your own risk.
1. Make sure you have Motorola drivers installed - [Download Drivers]
2. Download the MotorolaOneClickRoot.zip file from above and unzip it to your Windows PC.
3. On your phone go into Settings>Applications>Development and check the box for USB Debugging.
4. Plug phone into your computer and select “Charge Only” mode.
5. Navigate to MotorolaOneClickRoot folder and run MotorolaOneClickRoot.exe.
6. Follow the instructions in the command window.
7. Your phone will complete 3 steps, rebooting along the way. When it finishes, you will be rooted.
How to unroot your Bionic
*Pete’s root tools will also root your Bionic as well. This is a dual-tool.
1. Download and unzip PetesMotorolaRootTools.zip onto your Windows PC.
2. Make sure the Motorola drivers are still installed.
3. Make sure USB Debugging is still selected.
4. Connect your Bionic to your computer.
5. Run the Pete’s Motorola Root Tools.exe.
6. Select UnRoot My Phone at the bottom.
7. Your phone will reboot 3-4 times as the program goes through all 4 steps in the process.