Scaling navigation with hide function?

hi everybody,
i took a look at many menus and treid to find the right one for me. I think I’ve found it:

http://www.albindelasimone.com/

at the bottom, theres a menu that scales in relation to the mouse position. an when you roll over it comes up. the selected item is shown also when it’s closed again.

I have no idea how to realize this. I only worked some times withe the laco tweening class but how can i build up that really cool menu?

any help is appresiated.

thanks in advance