Hmm.. sounds nice ^^ Good site then, and I'm almost positive that that effect would be JQuery. Sounds like a fun animation that JQuery would be able to do efficiently and make it look awesome.

Judging from your site, you graphic design, but I would recommend not inverting the gradient (pushing the button down) until the a:active state, because hovering over shouldn't look like a push (not all but many cases). I really like the design though. That's usually the hardest part with me because I really like to focus on code haha