Just download the official update-file from the Google servers, and put it in the root of your storage. That's where your stuff is ( /mnt/sdcard ).
Power off your phone and hold the "Volume Up" key while pressing the power button. Then you can choose "recovery" via the volume up/down buttons. Then you see a triangle on the screen. Hold power and press "Volume Up" again. You will get a list of options. Select "update" and the update starts.
Don't get nervous, don't remove the battery. Just keep waiting, it could take a while.
Have fun with 2.3.4.
Update: There are 2 version of 2.3.3. That's GRI40 and GRI54. Meanwhile there are updates available for both version. But not all version of GRI54 can be updates. My own Nexus S brings up an error message. I think some of us have to wait a bit longer...
[via Android Central]
Oh and what's new? Video/Audio Chat on GTalk. FINALLY!
See the Video after the jump...