This came up in the Webinar today. He went over it very quickly so in other threads some wanted to know how to do it with a velocity envelope. Here's a few links to previous threads that deal with this in detail and especially some methods to do a slow down into the exact spot you want to freeze.

Freeze frames

How to slow down into a freeze frame

John Meyer's Secret Tip on hitting a freeze frame target

For me, velocity envelopes are very very useful -- especially when I think the key part of my shot needs just a little time MORE or a little time LESS.