Also, check out their fingerpaints:
What is the Best Paint to Use for Kids?
Not all paints work the same. The best ones to use for fingerpainting and handprint painting are tempera paint that is not too runny (I use Crayola paints). They should be labeled non-toxic and be sure to check that the label says washable. These are usually found at craft stores such as Michael's as well as stores like Wal-mart and Target. You may use acrylic paints, however, they dry on the hand really fast causing the print to not turn out very well with lots of gaps. Although they are non-toxic, they are not very suitable for children. They are not washable! Be sure to use these with caution and make sure your entire work surface is covered. Probably the most practical and cheapest would be to buy the powdered tempera paints. You can then mix them to the consistency you would like to use and you get more for your money. Just remember to store the leftovers in an air tight container.