I'd like to create a drop down list on my site. Basically when you click on or mouseover a link I want a list to drop down for available options. I'm not sure if this is a javascript thing or strictly a flash thing. Can anyone point me in the right direction on how to do this?

http://forums.edmontongolf.com
http://forums.golfingcalgary.com

Note: I'm not too interested in the standard drop down list. I'd like it be a mouseover where it auto drops down over top of the page. Perhaps it's more of a flash thing.