Well said by Erik and a few others here - "secrets" are few and far between in golf but this is certainly something that is not emphasized enough by golf instructors to their players.
Let these photos speak for themselves please. Then, if you are still unsure of whether the hips/belt/tailbone/lead knee, etc. are moving forward continuously in great players just keep looking at video anywhere you can. Forget what the players are saying and look at what they are doing. Couple things to note from my quick look at this thread:
1. Erik mentions Kenny Perry and his footwork - it is well done