Cases for the iPod Touch are scarce, most of the usual manufacturers haven't hit the market yet. I've stopped at the Apple store the last four weekends and the standard answer to "when?" is "I don't know". Yesterday I saw the first case in the Apple store - a bright pink neoprene one by InCase that had a belt clip on the back. When I asked about others, I was told that they had had a black leather InCase, but it had quickly sold out.
I'm actually waiting for one of Griffin's cases - either the Elan or iClear. In the meantime, I'm treating my Touch with kid gloves - I used a plastic screen protector on the back, I store it in an iPod Sock and put that inside a padded zipper case. I don't want major scratches on the chrome back, and while the front is supposedly scratch-proof, I want a substantial enough case to protect the whole thing in the event I'm a klutz and drop it.
There are LOTS of cases for the iPhone, so I guess patience is the key.