The Williamson download is good, although you're better off figuring out your own body language and thinking about your own sense of timing than duplicating his little finesses. Actually, the best thing on the top change I've come across recently is this conversation on the top change vs. the double lift between Andrew Musgrave and Tyler Erickson.
http://sleightly.com/blog/2011/03/04/63365-audiolog-tyler-erickson-talks-about-the-dl-and-tc/
It's free, and there's a ton of good information here. Most importantly, it stresses that the top change is not 100% burnable, and it's a mistake to treat it as if it is. It really is about timing and misdirection.
It's funny you mention this, I recently listened to this as well as their discussion on the pass. It was amazingly simple to follow, although it was a bit tiring at times.
As a side-note, the Musgrave and Erickson talks are
very enlightening. Worthwhile discussions for any serious student of card magic.
Now, on to the part that matters the most: A second vote from me on timing and misdirection. Rhythm is everything on it. I'm not saying you have to have them burning the deck to do it, but I'm not saying you have to have them looking at you either. I've had people look at the deck while I did a slight neck-tie or wrist kill action. Rhythm is key to a deceptive top change. Of course, not looking at the pack is the preferred route to go with the top change.
Other then that, I say re-read Erdnase and get the Williamson download, if you haven't already. You'll benefit from both if you adapt the top change to yourself.