as we all know that Samsung Galaxy S is run on Android 2.1,and soon it will updated with latest version of Android 2.2 (Froyo), but it will come till end of this year although an Android 2.2 firmware has been leaked and made available to install now,showing the firmware version I9000XXJP1 and is a 252MB download

Before you download and install this firmware on your Samsung Galaxy S, it must be noted that this is a test firmware and some features may not work properly, there is no support for Flash in the web browser.

note that this is only test version so if you can wait then wait for September when official it will available for your phone, so we advice to wait for final version.

check out more details here