E.K.
Check out Signing Time on PBS! What a great show! They have DVDs available. It's a hearing mom with her deaf daughter and hearing nephew and they go on adventures and use signs for what they discover.
There are some GREAT board books from Garlic Press (go to their website)that have basic signs.
I started with "more, all done, hungry, thirsty, please and thank you".
Keep in mind that your child may not repeat the signs perfectly. For example: the sign for "Thirsty" is to draw your index finger from just under your chin down your throat. My daughter instead put all her fingers to her lips and tilted her head back. For that situation, the important thing was communication. I knew what she meant-she was thirsty! Later they refine their signs as their fine motor movements are refined.
Also I hope you seek out ASL as opposed to "Baby Signs" language system. ASL is a true language while Baby Signs is a trademarked language system. Baby Signs DOES assist in communication with your baby, but it can't continue beyond that. You can't communicate with deaf people, you can't count it as a foreign language for school, and it is not neccessarily easier to learn than ASL. ASL is a language that your child can grow with, communicate with others, use for school language requirements and is relatively easy to learn. OK, rant over.
Good luck! I love sign language! If we live near eachother we could meet at a park and practice!
E.