According to Samsung's official UK Twitter account, the Galaxy S (the non-U.S. version, anyway) will receive Froyo (2.2) near the end of September; it is currently in development, according to the spokesperson. 

There has been a Froyo ROM leaked for the international version of the Galaxy S, so if you can't wait, try that. But it's nice to know that Samsung appears dedicated to its Galaxy S phones and is looking to update them as quickly as possible. (Via @SamsungUKMobile)