How can I use my iPod touch as an external disk? I have a 2nd generation iPod touch (8GB), but I don't know how to make it work as an external disk. I think I saw a checkbox somewhere but I can't find it anymore. 

I've searched the Web, but the way it should work (as a check box on the front page of iTunes when the iPod is connected) doesn't work for me...

Am I missing something or is this not possible anymore? I had an iPod nano that worked in the manner described.

Edit: I would like it to work with a Mac, a PC, the USB port of a DVD player, etc. (as with my good old nano)
I don't think it is possible using iTunes.

You can try iPhone Explorer, though (which is free), or Phone Disk