We found out that on the Nexus S and the Galaxy S the modem could possibly spy the main CPU(where Replicant runs).
We are currently trying to see if that can be fixed(by loosing about 80M of ram) or not.
More details are available on our wiki
As it was announced a few weeks ago, we are now releasing a new set of Replicant 2.3 images including Galaxy S support. Nexus S support was also improved, mainly on the modem part (there is now basic data support). Data should also be fixed on Nexus One with this release. More details are available in the detailed changelog.
You can download the new set of images:
Our Wiki was also updated with new pages regarding Galaxy S: