The hackers at XDA Developers have been hard at work trying to port Android 4.0 Ice Cream Sandwich onto the Android Kindle Fire. The first success was made in early December when a limited version of ICS was run on the Fire. Last week there was a breakthrough in what the XDA coders are calling a "pre-alpha" of the fire running an actual version of the newest Android OS. See the video below.
The newest hack of Ice Cream Sandwich on Kindle Fire is based off of CyanogenMod 9. According to the XDA Developer Forums, CyanogenMod 9 is not all that fundamentally different from the standard the stock edition of Android Open Source Project (AOSP) Ice Cream Sandwich. That does not mean to say that CyanogenMod 9 will not fork away from ICS and bring additions to the custom ROM, but for now there is little different in the code bases.
XDA developer JackpotClavin released the "pre-alpha" last week and the XDA community has been building off it since. Previous work on bringing ICS to the fire was done by an XDA member know as g1011999 who has made significant progress.
There are still several bugs to work out of Android 4.0 on the Fire. Wi-Fi is working (the all-important first step) while video playback and some audio are not yet working. That is significant progress for the project that had stalled (in terms of updates) through the middle of the month.
The work of g1011999 was built from CyanogenMod 7. Prerequisites for building ICS on the Fire include installing custom software such as CM7 or TWRP 2.0 after rooting the tablet. Then perform a factory wipe of the device and install JackpotClavin's work.
Currently the biggest obstacle is getting the SD card to save files from the device. That has been the most recent fix but still remains a work in progress.
Here is a video of ICS running on the Fire.
To follow the discussion on XDA discussion boards, see this thread based on JackpotClavin's pre-alpha launch. The thread was split from this thread that details the work done by g1011999. The IRC associated with ICS on the Fire is located at irc.freenode.net/#kindlefire-dev. To learn more about CyanogenMod 9, see the company's blog here or join the CyanogenMod forums here.
As this is a "pre-alpha" the current build of ICS on the Fire is not really ready for public consumption at this time. If developers want to help in the work of bringing ICS to the Fire, go jump into the XDA Forums or the IRC and volunteer your expertise.