Research shows teaching your baby sign language may reduce frustration and tears by improving communication. For example, babies can use signs to ask for what they want.
I started watching Baby Signing Time! DVDs when my daughter was four months old. I learned the songs and signs from the videos and then sang and signed them with her. I made American Sign Language songs (like Apples & Bananas and Baby Needs a Diaper Change) a regular part of Infant Story Times at the Burien Library.
If you're interested in learning more about baby sign language, here are more resources:
The Baby Signing Bible (book)
American Sign Language for Babies & Toddlers (streaming video)
Baby Sign Language Basics (ebook)
Here's a preview of Baby Signing Time: