Magnifying menu

Anyone know where I can find a tutorial to make a magnifying menu similar to this:

menubar

or know a way I can achieve something similar to this. Much like the magnify effect in the OS X dock.

I have an idea on how I can get the item to magnify when the mouse rolls over but its the items either side that have a slight magnification also thats posing the problem for me.

Any help would be much appreciated.