I'm not sure what has gotten into the folks at Samsung as of late, but they seem to be on top of their game. They dropped the source code for the DROID Charge and Fascinate last week, the Gingerbread update for the Galaxy S started rolling out for European users this weekend, and this morning, the source code for the aforementioned 2.3 update hit the Open Source Developers Center. Ergo, we can almost certainly expect to see some custom Gingerbread ROMs for the Galaxy S in the coming weeks.
To download the source, head over to the Open Source Developers Center, search for "GT-I9000_OpenSource_GB.zip," download, and enjoy.
Source: Open Source Developers Center