OTA Update 5.1.1 (build 9B206) is an official Apple over-the-air update for the iPod touch 3. The update package is 105.59 MB. This is a delta (partial) update that requires 5.0.1 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: c88ad76d109844cf97e53f6bd8e2c13f3e657574.zip.