This is the place to go if you need to restore the original OS for your ipod, iphone, ipad.

This is required if you are not happy with your jailbreak or need to update the previous version.  However, please take note that you need your iTune as well in order to perform software restore.

Well, you will require your old iTune apps in order to install all the sn0wbreeze patched. Here you could find the link to old iTunes.

For 2G iPhone iClarified is the best depository for ipsw restore.