Why don't I have a camera on my iPod touch?
As far as I know, only the 4th gen iPod touch has a camera. Yours is probably older.
As you can see from the specifications published on Apple's site, there are no mention of a camera for the third gen iPod touch, while the fourth gen has detailed information about it.
Only the 4th generation iPod Touch has cameras, that is the iPod Touch that was introduced back in September. The iPod Touch you have is either a 1st, 2nd, or 3rd generation, which means it doesn't have the camera.