You do get a special pass that you show to the parking CMs and they direct you to the special diamond lot. We had one last December courtesy of a wonderful DIS'er. We went to epcot around 4PM on a couple occasions- it was really nice to park right up front (just past the handicapped parking) and walk in. Otherwise, we would have been at the very back of the lot and would have to wait for a tram. If you're going to the park at odd (ie not at the rope drop) times, it can be a big help!
Also, the pass is good for the calendar year, so when you get back, you can sell it on ebay or offer it to someone here.
HTH!
Liz