Glenn Fleishman over at Wi-Fi Net News had a chat with Eric Tews, one of the researchers reported to have come up with a crack for WPA’s TKIP encryption. Glenn has posted a good summary of what he found has really been discovered.
The short story is that if you are using WPA/TKIP, you have little to fear from this exploit. You are more at risk from using a weak passphrase, whether you are running WPA/TKIP or WPA2/AES.