Creating a network bar.

i know that Nightspy recently opened a topic aksing how to code his network bar but i would like to know how to create one basically from scratch, except for the design part coz i have that covered.

how do i get the network bar at the top of every page, is it a frame?
how do i add drop-down menu's, and when i do do i have to edit it for every site?

these may sound like stupid questions but im more design than coding.