Baby Sign

I had read about some families' use of Baby Sign—using manual gestures in addition to words to communicate with very young children, under the theory that the children are capable of language in abstract but acquire manual dexterity earlier than they acquire sufficient control over the vocal apparatus to produce reliable speech (if I understand the premise correctly). Apparently, it helps children communicate with their environment earlier, more effectively, and more successfully than with speech.

It sounded interesting, and I considered doing something like that with Amy; at eighteen months, she has a couple of words but not very many, and is still often reduced to pointing, dragging your hand to something interesting, or merely giving up in frustration when she's not able to communicate her wishes, and at least one site I browsed suggested that while many start early (one place said seven months, another even at birth), even a later start will help the child.

That kind of brought up the question of what system of signs to use. American Sign Language? British Sign Language? German Sign Language? Some commercial system/something proposed by a particular website [for example, one with simpler signs designed to require less dexterity from a baby than an existing general-purpose sign language]? Something I think up myself?

On the other hand, I doubt the idea would ever take off since I rather dislike learning vocabulary (it's my least favourite part of language acquisition) and I fear I'd have to learn a fair number of words in order for the project to be useful. If I use some ready-made system, I'd also want a useable dictionary handy for me to look up new words in (and if I grow my own, I'll probably want to notate them somewhere to remember what sign I used for what thing).

Do any of you have experience with Baby Sign in any way, shape, or form?