While Samsung has said there would not be official ICS support for the Galaxy S (I9000), XDA dev PaulForde has been hard at work (with the help of a nice list of users) making sure the unofficial support is there. The ROM, based on Android 4.0.3, is at RC1 status as of this evening.
His list of things currently working are:
RIL (Calls, TXT, Data)
Both SD Cards
Camera(Video Recording & Pictures)
FM Radio(Download Spirit FM from Android Market)
What does not work:
Wireless tethering(stuck at acquiring IP)
Here’s a video on the ROM, and follow the link to the XDA thread for more information.