That site seems ok at a glance. There are lots of good sites out there.
Just make sure that you are using real ASL (Amer. Sign Lang.) signs with your child, not some dumbed down version, which some baby sign language programs use.
Think of it as talking to your baby like, "Awww wook at the wittle baby-waby." and then trying to figure out in a year or two why your child can't talk right and no one understands him.
