Motorola Droid 4’s first Official ICS build leaked. It’s the original build from Motorola and its available for installation. This build needs more work before deployment. So, guys be careful and trained or adventurous people only install it. Those installing now may fall victim to the tendency for leaks to not so easily revert to manufacturer approved software when flashed with available fastboot files, often resulting in a bricked phone.
To install follow these instructions
1) Your droid 4 must have root access
2) Download cheesecake http://www.mediafire.com/?b30nhumk4i960hg
3) Choose the first option: click to create proper files
4) Reboot
5) After reboot choose 2nd option: click to change server:: choose staging-and click the only option that says 100 master something.
6) Check for updates download and enjoy before moto finds out!
7) It will say something when checking for update just click setup and wait, download will be almost 400mb but worth it!
Source: DroidForums