What your looking for is most commonly known as a graphics tablet, sometimes referred to as a digitalize tablet, or a hyper tablet or hyper pen.
Usually it is a combo kit of tablet, pen, mouse.
They are available just about everywhere, Best Buy, CompUSA, Large computer stores, and all over on line. Usually they are located with the keyboard / mouse grouping. Some are corded some are wireless between device and tablet. They have become so popular that I even saw one at CompUSA in their private label. Seems like it was pretty cheap.
Prices vary widely from around 65.00 (brick retailer) on upwards to a couple hundred dollars.
Accuracy, size of tablet, and features dictate price.
I think the premier name in these has been WaCom
with another being AipTek - stocked at Best Buy, but there are several others.
Not sure of which is the best, not my area, but here is a site that probably will tell you more than you want to know about them.
http://graphicssoft.about.com/library/weekly/aa001213a.htm
You might also look at sites on the web directed to graphic artist or cad designers for more info.
Hope that helps get you going in the right direction.
