"Ice Cream Sandwich" is Google's cute nickname for Android operating system version 4.0
The Droid3 was made available mid July 2011, and at that time the latest Android operating system for phones was still Gingerbread, which was version 2.3, so that's what was running on the Droid3.
Ice Cream Sandwich was already known to be nearing release back in July 2011 and it was to be a major update for Android, so buyers like me were glad to hear that the new Droid3 would receive ICS soon after it was released and that the Droid3 had plenty good specs for running it. That never happened, and now we are told it never will.
ICS was released by Google on 19 October, 2011, and was "theoretically compatible" with any phone running Gingerbread, like the Droid3.
Instead of updating the Droid3 to ICS, as buyers had been led to expect, Verizon and Motorola put together another new phone, called the Droid4, which was mainly different in that it had a 4gLTE radio in it, instead of the D3's 3g radio. The Droid4 shipped after ICS was already released, in February 2012, but it still had only Gingerbread Android on it, not ICS. After months of impatient waiting, Droid4 owners were eventually told they would, someday, get an official OverTheAir update to ICS, though that has not happened yet, still. Droid3 owners were told they would not get ICS afterall.
The Droid3 is a great phone running a fairly stable, now, finally, version of Gingerbread, and that is pretty much what it always will be. Developer interest in the phone started off pretty strong, but has been stymied by a locked boot-loader and difficult to work with hardware drivers. So, there has never been, yet, a fully functional and stable independent ICS replacement for the Droid3, although there are some interesting and useful efforts if you want to get into them. I still run my Droid3 stock, which means Gingerbread.
My new phone is coming in early next week and it is a Google Galaxy Nexus with Android 4.04 on it (ICS). It will receive JellyBean, Android v4.1, someday, probably in 2012, we hope, unless Verizon blocks that like they did with ICS on the Droid3.
I believe the Droid3 is the only Motorola Droid phone that will never get a single Android system update. Great keyboard, though.