I've done this quite a few times & had small trees growing at my parent's house. They make nice little house plants when small, but will get big eventually & won't produce fruit with the same quality as a commercial avocado. I'm not trying to be a downer as growing them is fun regardless!
If you haven't already read the Wikipedia article, it seems to contain a lot of good info.
http://en.wikipedia.org/wiki/Avocado...and_rootstocks