We know that Android 4.0.4 will be coming relatively soon — a version for the Verizon Galaxy Nexus leaked last night, and now developer Jean-Baptiste Queru has noted in the "Android Building" Google group that he's pushing the Android 4.0.4 files into the Android Open Source Project. Queru says that this update will bring "a few hundred changes over 4.0.3," though he doesn't get into detail on what those changes will be. He also says that the version he just pushed matches the one that was sent out yesterday (and promptly disseminated by the hacking community).
While this confirms that Google's getting close to having a final version of 4.0.4, we're still a ways from it being pushed to users' handsets. Queru says that he doesn't know the schedule for deployment, "especially in situations that involve additional per-operator customizations done by the device manufacturers and / or in situations that require operator approval prior to deployment." The short of it is that we'll still be waiting for carrier and manufacturer approvals before this makes its way to handsets.