The biggest announced new features in the new iPod touch (2nd generation) are that it now includes a built-in speaker and hardware volume controls – serious omissions from the first model are now addressed. What wasn't mentioned in Steve Jobs' presentation yesterday was that that the iPod touch now also supports a microphone via Apple's new headphones.
Job's mentioned that Apple's new In-Ear Headphones (coming soon at US$79) and more traditional Apple Earphones with Remote and Mic (coming soon at US$29) would be recognized as a microphone for recording voice memos on the iPod nano (4G), but neglected to say anything about microphone support on other iPods.
The product page for the new earphones says that the microphone feature is also supported by the new iPod touch (2G) and classic (120GB):
The remote and mic are supported only by iPod nano (4th generation), iPod classic (120GB), and iPod touch (2nd generation).
This is boon for iPod touch users that previously had to hack together an external microphone that could be used for VOIP applications such as Skype. MacRumors notes that Apple has said that it won't restrict Wi-Fi VOIP applications as long as they don't run over the iPhone's cellular networks. They also note that it could be a misprint and that the feature has not yet been confirmed by Apple.