There is a BB Code Manager that allows a site admin to create and update BB codes (the markup enclosed by square-bracketed tags), according the the vBulletin online docs. It sounds like it is pretty easy to use.
Strikethroughs do not work! Actually, they do now. Place around whatever you want, minus the asterisks (*) and it should be strikethroughed!
Strike that! (This was one line) Daniel, currently this expands to a DIV tag; if you change it to a SPAN tag it won't cause a line break before and after the strikethrough. Alternately, you could expand it to a STRIKE tag instead of a style specifier. By the way (Eyez or anyone else), anytime you want to see the BB code that created an effect, hit the Quote button and you can see the code in the editor pane.
That may be more difficult. I'm not sure whether the BB Code Manager supports that. And thanks, Daniel, for the rapid fix!
^ hah. Yup. There's a field for "button image/url" or some such thing. All I had to do was enter the url to the image.