Hi,
From where did you download the SDK 3.0 for iPod Touch ?
My iPod Touch has the 3.0 GM firmware (the previous build before the 3.0 final) and I can't download a new one from iTunes (it says that it already has the newest version) and I can't download it from the developers page. It seems that the firmwares are not available for download anymore.
I had no problems in downloading the firmware for the iPhone from iTunes.