The file in that link is only for Nexus S phones upgrading from build number GRI40 – stock Android 2.3.3.
- Download the file, rename it update.zip and copy it to the root directory of the sdcard storage
- Reboot the phone into the bootloader by holding the volume up button while pushing the power button
- Use the volume down button to highlight recovery and push the power button to select
- You’ll see a triangle with an exclamation mark in the center. Hold the power button and then press volume up and use the volume key to select “apply update from /sdcard” and press the power button.
Video chat works OK over WiFi. I haven’t tried it on a 3G connection yet. The Google Mobile Blog post says, “You can make calls over a 3G or 4G data network (if your carrier supports it).” I’ve read a couple of anecdotal posts that said it didn’t work on T-Mobile 3G.
Another improvement with the Android 2.3.4 update is that it seems to help the GPS in the Nexus S. The last time I used GPS Status and Toolbox, it took about two seconds to acquire a fix.