I taught a few of my friends last year and this formula seemed to work really well:
First, as mentioned before, let them stand up on the skis and get used to being in the equipment before actually taking them out on the slopes. This will let them get the feel for how their weight shifts and how the concept works before actually putting them in the hot seat.
Then, take them to the bunny hill and teach them the basic pizza-french fries deal. The biggest fear for new skiers is stopping, so once they know how to stop, their confidence should go up and they will be more willing to get a little adventurous. Give them like 2 or 3 runs of this until they've really got the feel of stopping and going.
Next, I like to teach them how to turn in the pizza position (it has some fancy german name, but basically its just putting your tips together and then gently pressuring one ski more than other to make a slow, snowplow turn). Start on one side of the bunny hill, have them follow you across the fall line all the way to the other side, and when you get there, tell them to stop (pizza) and then demonstrate how to turn and explain the whole weight transfer thing. Let them try, and repeat.
From there, they'll pretty much have learned the basics. Keep taking them from one side to the other and back until they get more and more comfortable and want to try getting a little more speed with their turns. If they do well, take them on a slightly more difficult green and just let the magic happen.
hope that helps.