Hopefully you'll have something like my final image, or even better. Personally, I feel that this image needs more work, and was a quick and dirty job. I would have spent more time creatng the mask more carefully in the edges, but I think it's fine for our purposes.
Lastly: Photoshop is amazing in the multitude of ways a user can do things. Notice the two masks we painted in this tutorial were essentially the same. There is a way to save the mask after you make it the first time so you can re-apply it later without having to paint it again . . . but that's for another tutorial.
-Erik
Please post Questions/Comments below.