What do you mean?
Sent from my Nexus S
Is this what you were asking about?? Or was it the market part??
To install the latest Nexus S build GRH78C, follow these steps:
Download the update file from Google’s server:
GRH78C-from-GRH78.zip
Copy the file to your phone’s internal storage (/sdcard). Tip: The Nexus S can flash any file so there is no need to rename it update.zip
Power off your phone.
Hold down the VOLUME UP button and power it back on.
Use the volume keys to navigate to recovery and press POWER to select it.
When you see the “/!\” symbol, hold the POWER button and then press the VOLUME UP button.
You should be presented with the Android system recovery menu. Select the option “apply update from /sdcard”
Find the update file (GRH78C-from-GRH78) on your sdcard and then press the POWER button to flash it.
Wait for the update to complete and then select “reboot system now”