After hearing that the ICS OTA is being pushed there will be a lot of people looking to root ICS. I know we have an awesome Droid4 Utility by Jsnweitzel that does everything but these people who are getting the OTA really only want to use the root function. So here is the link to the root tool created by the same gent who made Motofail for gingerbread.
1. Download the root app here:
http://t.co/mbIAmwH8
2. Make sure you have the latest motorola drivers:
USB and PC Charging Drivers - Motorola Mobility, Inc. USA
3. Connect the phone to the computer using the USB cord.
4. Unzip razrs_edge_windows.zip
5. Make sure your phone has USB Debugging on (setting > developer options > USB debugging)
6. Also make sure you're on MTP mode, not mass storage.
7. Open the razrs_edge_windows folder, navigate to "run", and press it.
8. Keep the phone connected to the computer until it's finished. It shouldn't take longer than a couple minutes.
NOTE: I haven't personally used this tool, so if it went through successfully and you still don't have root then go to the Market and download Superuser and Busybox.
INSTALLING A ROM
Now that you're rooted you may want to try installing a ROM. Jsnweitzel will be updating his Droid4 utility which has the option to root and install Safestrap. In the meantime, here are the instructions
How-To Safestrap « Hash-of-Codes on how to install Safestrap and the download for Safestrap 2.0
http://bit.ly/JDodBs
The instructions explain what Safestrap is, how to install it, and how to install a ROM. I highly suggest reading it and understanding it. As far as ROMs, Eclipse has been the most stable and is my personal favorite
http://www.droidforums.net/forum/droid-4-roms/219332-rom-port-eclipse-ics-1-2-a.html If you want to try other ROMs there is CM9 and AOKP which can be found in the ROM thread
Droid 4 ROMS Personally, I am waiting for CM10 which is supposed to have Jellybean attributes, but that ROM is still being worked on.