Slide in menu

Hi, I’m looking to create a menu system that works the same as that used by http://www.ninedots.com ,

not the little dots, but the smooth sliding drop down menu at the top (levi, nike, molson) how do you make it:

a) so smooth
b) make it so that as you rollout of one it falls back into place smoothly - i can only use the over setting on buttons to make it come out and snap back on rollout

any help / demo fla files would be helpful, and if you tell me to ‘search the forums’ can you include what to search for as i couldnt find this kinda thing.

many thanks to anyone who helps