I just spent the whole morning trying to fix the key that I stupidly removed from the keyboard (because it wasn't working, and I wanted to clean under it.) I eventually found these instructions, which were very helpful:
http://docs.info.apple.com/article.html?artnum=88106
The back of the key isn't exactly the same on the MacBook Pro, but the scissor mechanism is. For me, the problem was that the scissor mechanism came apart. It has TINY holes, to connect the two. Once I got the scissor mechanism back together properly, I followed the rest of the directions and was fine. (And as you can see, my "N" is working again 😉
