Check out these:
Paint Cost Estimating
This one wins 'most bang for your buck' award, at only $49 to purchase. Better yet, download the free version, and play with it awhile to see if it will work for you.
PEP Paint Estimating
This one is a little more complex than the one above, and costs a bit more. The basic version is $199, and the pro version (which includes job costing, additional reports, and application rates feature) goes for $249. Once again, download the free trial version, and test drive it.
National Paint Cost Book
This one is a book which includes application, & material rates, along with a simple estimating program on CD that already has the rates built into it. Costs about $50, you can find it used for around $25, but it might not have the software still in it.
And there are others out there, more complex and expensive, but to start out with, these will work fine. It will at least give you an idea how they work, and will show how important your production rates are to price jobs out correctly and consistently.