As promised earlier this year, Google has published the source code to their Android OS version 4.0, aka "Ice Cream Sandwich". The popular open source Android OS powers a wide range of smartphones and, increasingly, tablet devices.
There was some concern about whether Google would fulfill their open source commitment by publishing the ICS source code, because the source code to the tablet-oriented Android 3.0 "Honeycomb" was never released. According to Google, their reluctance to released Honeycomb was due to its "rushed" development and issues related to code quality.
Regardless, Android 4.0 ICS is intended to replace prior versions of Android and unify the OS for both smartphones and tablets. Official vendors like Samsung and HTC will decide which devices will either upgrade to or launch with ICS. But because the ICS source is now published, intrepid developers can build their own versions of ICS to produce "custom ROMs" that may run on devices that never receive official support.