no, it does not have a microphone. The new headphones, however, will have one.
Correction- ANY 3.5mm headset with an in-line microphone will work. It just has to have a connector that looks like this:
Regular headphones only have three contacts on the end that plugs in, but the headsets that work with the new Touch have to have an extra one at the bottom. That picture is of a headset that is currently being marketed for the iPhone.
from my understanding you can use a mic for both 1g and 2g but the 2g allows you to plug the mic in the headphone jack and 1g you can only use a dock connector mic
Is that correct?
I have no idea if Apple-sanctioned apps will work with a dock connector microphone on the old one, but I know some jailbreak apps will.
As for the 2G Touch- If you can get an app that uses the microphone to install (and not know it is on an iPod Touch) it will work.
The only two on the App Store that work currently are Spectrum and Palringo IM.