The first upgrade improved the responsiveness of the Swype keyboard, which comes pre-installed on the phone, and also repairs some connectivity issues on the unit. The second update for the Samsung Galaxy S II fixed a problem that the handset had been having with its' auto-brightness control.
To grab the update, you need to hook up your Galaxy S II to the Samsung Kies app. And the firmware is rootable, which should put a smile on the face of many of the device's owners.
source: AndroidCommunity via Engadget