Well the 2.0 firmware isn't available on iTunes for everyone in public right now. You'll have find it on your own. 😛
I'm not sure if anyone has been able to upgrade directly from 1.1.4 to 2.0. The only way I know out there so far is with the PWNage application but that requires you to completely reformat your iPod touch. Also, Installer isn't fully supported on the 2.0 firmware so you won't be able to run most of your jailbroken applications.