I don't see how it would work unless the iPhone headphones somehow function with the touch. Skype on iPhone is a TOTAL WASTE.... it works through safari and basically the web client calls your iPhone and when you answer it connects the two calls. You effectively use both data and voice minutes to use it. At this stage, it has absolutely ZERO use with iPhone. Some misinformed people claim it is useful for making international calls but it is really useless at this point. For skype to work as advertised, a legitimate native app must be made.
Ah, you raise a good point. The Touch doesn't have a microphone, as far as we know anyway. So even if a genuine application was created that we could hack onto the iPhone springboard, we couldn't use it for the Touch.