It’s pretty sure now that the Galaxy Tab will not get the ice cream sandwich update but there’s a good news that you can have ICS unofficially. All credit for this goes to dev from CyanogenMod. Most of the people will be awaiting this update.
The Galaxy Tab received a port of CyanogenMod9, its almost working with some lag. But still the camera is not working and possibly there could be a few more bugs, the improvements are still going on. Very soon we could see the official release of CyanogenMod9.
You can check the link below for the XDA developer thread that gave this information.