Since I'm seeing questions inquiring about Android 4.0's source code drop every 5 minutes here and there, I thought it would be a good idea to point out this blurb in a recent post by an Android engineer Dan Morrill, aka morrildl:
To reiterate, these servers contain only the ‘gingerbread’ and ‘master’ branches from the old AOSP servers. We plan to release the source for the recently-announced Ice Cream Sandwich soon, once it’s available on devices.
Since the Galaxy Nexus is the first ICS device, rumored to go on sale sometime in the beginning to mid November, we shouldn't expect the source code to be publicized until about that time either.
As I mentioned yesterday, this means CyanogenMod and other source-based ROMs are all on hold pending this release (if you're confused about the differences between source and SDK, hit the same link).
It's also worth pointing out that not seeing the source right after the announcement is normal - in the past, Google usually took about a month to get it ready.
Source: Google Groups, thanks Justin