You sure it's gone? I have forgotten where I have moved an app before. Try going to the search page and typing in the name of the app. If it's not there still, reset your iPod by pressing the power button home button and volume DOWN button all at the same time. hope I helped!!
Did you create folders? If so, you may have forgotten which one you put it in.
It CANNOT be deleted.
If you can't find it, then type "settings" in spotlight search, it will surely appear. (for spotlight search: touch home button once to go to the first page and then press home button again) of course, if you already are on the first page, then you only have to press home once... just in case!!!)