Pixologic has teamed up with Mike Pavlovich to produce a series of tutorials detailing the new Dynamesh features in the latest Zbrush.
The first three videos in the series are posted already here as of this news posting. I highly encourage you to spend some time with Mr. Pavlovich if you are a ZBrusher. Even if you don't recognize Mike's name, I'm pretty sure you've seen his work. He's got a couple handfuls of videos already out there to his credit. And beyond those, he continues to hold down a day job as well at Certain Infinity. The character he uses in his newest videos come from that day job as well.