It's about 30 miles north of Kansas City.
Here is the address:
646 South Kansas City Avenue
My favorite BBQ in Kansas City is Smokehouse. I think Gates is over rated and it's usually dry. You may want to head a bit north of KC to Excelsior Springs and check out Wabash BBQ.
I agree with chileheadmike about Oklahoma Joe's. It's also very good. There is always a huge line when I'm there.
Bryant's is decent too. Their original sauce is an acquired taste that I don't like but they also have a sweet heat sauce that is really good.