How do I go about getting black buttercream icing? I have used jet black, and that does not make my icing black.

You aren't using enough... keep adding it until it's black. It takes a lot... you'll know when to stop!

It's easier to get black if you start with chocolate icing, otherwise your using a lot of black colour which can effect the taste of your buttercream

I 2nd the suggestion to make it chocolate first!!

If you can't do chocolate, have you tried Americolor Super Black? Don't forget, the buttercream will darken in another hour or so.

Another suggestion if you don't need TONS of black is to mix your own buttercream and a little black gel with some of the tubes of Wilton Pre Made Black icing. That icing isn't bitter, but adding too much black gel will make your icing bitter.

Make it at a day in advance and let it rest, the color develops over time.
Just color it a dark gray and by the next day you'll have black, no need to use a gallon of black food coloring.