great idea! They could even help you make them (if old enough) and choose what they want to put on them. Will have to remember it in a couple of years time when DD is at that stage
You wouldn't even need to wai until then, you could use pictures of things she likes NOW but make basic ones... do pictures of yourself and make an M for MUM card etc.

I would never have thought of making them for DD1 now but they are so quick at learning, and really it will prob cost less to make some for yourself with numbers, letters & colors than it would to go out and BUY 3 different wall charts... k-mart are selling alphabet wall charts for $12.99 WTF?????