ncHoverBind is a simple addon that does one thing: binding buttons on mouseover. You can mouse over actionbuttons, spells in the spellbook and macro's in the macro pane and bind them while hovering. You can bind keys, mousebuttons 4 and 5 and the scrollwheel with this addon. If you made a mistake in binding, you can just press "Discard" and your old bindings are loaded. Real simple!
Download and install. To start use either /hb or /hoverbind. Hover over buttons, spells or macro's and press a key, scroll with the mouse or press mousebutton 4 or 5. After you've bound your spell/items/macro's press "Save bindings" and your done!