Black tie does usually mean dinner jacket (black with silk or silk-look lapels), matching trousers (sometimes with ribbon down side) and black bow tie worn with a dress shirt. There are variations on this that even dress snobs argue about, for instance whether or not you wear a dress shirt that has a winged collar or the more normal fold-down shirt collar (I'd say the sticky-up collars are best left to your pretty-boy model types or for very very formal occasions when it's known that everyone else will be wearing them). I wouldn't get too worried though, these days black tie is being taken to mean just more generally formal evening wear, and so it's interpretation depends very much on how much you like to draw attention to yourself; my sister's husband wore a dark red velvet jacket with striped bow tie and black trousers the other evening to a do at a very posh golf club, and he's an old bore. Get the bow tie, the shirt and the shoes right, look comfortable in what you're wearing, and that should do.