This is a personally confirmed software update for iPod Touch 2nd Generation. If you are running any iPhone, or an original iPod Touch (1st gen) this will NOT work, do NOT try it.

To use this, enter iTunes, plug in your iPod, and do as follows:
Hold Shift and click restore (if you are on a Mac, hold Command and click restore). The browse to the saved file directory for the ISPW and click open. Presto, you should be running 3.0 

This file is virus-free, and is completely recognized by iTunes as official software... for all iTunes knows, you bought this form the store. Enjoy!