One of my favorite podcasts is a psychology podcast called "Shrink Rap Radio." Recently on Shrink Rap Radio Dr.Dave interviewed Nancy Hanauer,  a pioneer in the field of American Sign Language for hearing families. Nancy was one of the first teachers creating and providing classes in North America and this informative interview will answer many of the questions you may have about signing with your baby. You can find it here:

http://www.shrinkrapradio.com/2008/01/25/134-sign-language-for-babies/

FYI, I signed with both of my children when they were babies and LOVED it! It was a great way to know exactly what they needed, when they needed it. It's not hard. Even though I am fluent in American Sign Language (I used to be an interpreter) I only taught my children about 10 signs (eat, drink, more, bathroom, pain etc)  It was so helpful and did not delay their langugage development at all!

 If you are ready to learn to sign with your baby, and don't want to take a class, I recommend the excellent guide here:

http://www.solutionsforbusymoms.com/signing4babies