Apple updated the firmware for iPhone and iPod touch to 3.1.3 which fixes minor issues like the app crash issues facing some 3rd party apps and a better enhanced and accurate battery level display. If you cannot see the upgrade option on your latest iTunes 9.0.3 or you do not want to download and upgrade/install from there and here are the alternate download links for you:

Download iOS/iPhone firmware for iPhone (2G, 3G, 3Gs and 4), iPod Touch (2G and 3G) and iPad

Direct download link for iPod is on its way so stay tuned.

Upgrading to iPhone/iPod touch firmware 3.1.3 manually:

Once you have downloaded the firmware. Upgrading to it is pretty simple. Follow these steps:

Open iTunes and click on your iPhone/iPod device:

Now press Shift + click Restore. A window will open up asking for the firmware with which to update your iPod touch OR iPhone. Give it the location where you downloaded the firmware and click Update!