A: 3/4 the size of our moon. I don't know actual kilometers/miles, but I like comparing it to other celestial bodies.
Q: Do you consider pluto a planet?
A: No, he's a dog. Now, seriously, i think Pluto is the frontier between what we call planets and what we call asteroids. It has a "moon", but it's only slightly larger than it. It's closer to the sun than the asteroids of that belt whose name i keep forgetting, but its orbit is way out of line compared to the other planets'. It's a really big asteroid but a really small planet. And so on.
A: Well, all you need to do is look up the definition of a planet to know my answer (hint: there is none ) Seriously though, I don't really accept the word planet. To me, all it really sums up to is 12 celestial bodies that are orbiting a larger one (I think they've discovered three past pluto, not sure thoug) BTW, you were thinking of the Kuiper belt.