SlixTop is very similar to BarNone II, published a few issues back. But there are a couple differences: first, a bug that caused BarNone II not to work properly on some systems has been fixed, as have other smaller bugs. Secondly, SlixTop looks very, very cool.
SlixTop works in the same way as BarNone II. When the menubar is in the "hiding" state, move the mouse to the top of the screen to make it appear. SlixTop will pull down the menus for you, as if you had the mouse button down. After you choose a menu selection or click the mouse off the bar, the menubar will disappear again. The other two menubar states are "locked on" and "locked off". To go between the three states, press OA-esc.
When you install SlixTop, you'll need to remove BarNone II if you have it installed. You should also remove the programs "ShadyBar" and "Bender" if you have them, because SlixTop incorporates them and goes beyond what they do.