I think as a whole black is an accepted color to wear in this day and age. You will probably be fine. I would call the bride or coordinator to double check. The last time I wore black to a wedding was many years ago, and I asked the bride in advance just to be sure.
Oh, I wouldn't suggest this. I still remember how heated a colleague of mine got with the whole "call up the bride and ask if the clothes are formal enough."
She was really frustrated. She had a ton of things to arrange, and take care of, etc. The wedding, with all its logistics; her move from one home to another.
She said, "Aren't these people grownups? I don't need to bother with someone else's attire!"
So, I don't think anybody should be calling the bride, or even the coordinator (how would you know who that was anyway?) and bothering her with your own wardrobe concerns.
If you can't come to a clear sense of rightness on your own, using resources other than the bride's time and energy (like, us here at EHell!! Or your neighbor, or a friend, or your mom), pick a different dress.
And I think black at a wedding is totally OK. (And my bridesmaids wore black tea-length party dresses with red sashes.)