The best videos we found when my daughter was a baby was Signing Time (they can be ordered online). They were GREAT! My daughter really learned and used the signs (milk, more, tired, hungry, thirsty, ball, book, all done, mommy, daddy, etc.) and she was really able to communicate with us much more efficiently, before she became verbal. Even after she was talking, she would use the signs sometimes to reinforce what she was saying - like if we weren't getting her milk fast enough when she asked for it, she would keep asking and signing it:-)
And best of all, they were cute entertaining videos with songs that weren't annoying. The whole family learned and enjoyed them. Down side - they are a little pricey, but well worth it. You maybe able to find them used on Ebay or Amazon.