So this worked for you? I'm going to a party right now, but I'm definitely going to do this when I get back! I HATE BEING IMPATIENT!
Yes.
BUT, there is an issue with the recovery on GB not working properly with ICS, so you have to actually install ICS twice. The first time it will fail, but it actually installs the correct recovery during that first time. These are the steps I took:
1. Download file from that site. Put on external SD Card. (important!)
2. Boot into stock recovery.
3. Clear cache TWICE.
4. Choose install from SD, and then choose the file you downloaded.
5. Install. It should fail, saying something about the TMP Package.
6. It will kick you back out to the Install from SD screen.
7. Choose reboot system, and IMMEDIATELY press Volume up/down and the power button. This will send you back into recovery. (I had to lift off these keys for half a second, then press them all again in order for it to go into recovery)
8. Clear cache TWICE again.
9. Install this same file again. It will take half the time and complete successfully.
Boom. ICS.