How to flash Nexus S (currently on custom AOSP build) with stock Gingerbread by Google (Android 2.3.3) I have a Nexus S which I have flashed with a custom Android build. Now I need access to the Android Market and some other Google services and therefore I need the stock Android from Google. 

How can I revert my phone back to Google's build of Gingerbread (Android 2.3.3 which includes Google apps)
Here's a full stock ROM for the Nexus S (via XDA): http://android.clients.google.com/packages/ota/google_crespo/f182cf141e6a.signed-soju-ota-102588.f182cf14.zip (MD5: 3e8908941043951da5a34bb2043dd1a0)

You should be able to name that update.zip and put it in the root of your SD card; upon reboot it will be installed.