Tennis4you's Workshop has some drill for beginners, also just regular drills as well. You can access the Workshop from the homepage.
If they have never picked up a racquet before you will certainly want to drill with them a ton. But as far as gettng them strokes quickly, that will be the tough part. Technically they will have to get use to the ball bouncing, how and where ot position themselves ec etc. I would give them a basic grip for their shots, show them at the beginning of each practice some example strokes and then let them go hit a ton. As they start to get better you can start to define their strokes a little more.
Sounds like a big unertaking, but it will be fun. Good luck!