The first thing you'll need is a device to actually capture your images. The two primary devices on the market for this task are the digital camera and the scanner. While a complete discussion of the differences between them is out of the scope of this article, there are a few things to keep in mind:

• If you are dealing with small sketches, watercolor paintings, or other such items, a scanner might work well for you. With a scanner, it is relatively easy to line up your art and good a nice clean scan. If you are dealing with large paintings, sculptures, etc., a digital camera is definitely the right item for you.
• The prices on scanners is literally a fraction of what they were a few years ago.  You can head to your nearest CompUSA, Best Buy, or Circuit City, and pick up a decent scanner for under $200 (the UMAX brands commonly sell for $99 or so).
• The prices on digital cameras, however, are still relatively wide in range. You can pick up an inexpensive one for under $200 or $300. Of course, the sky is the limit. You can pick up a commercial grade digital camera for between $10,000 and $15,000 - up to you. :-)  If you are looking for a decent mid-range camera, such as the Sony Mavica or the Kodak DC290, you can expect to spend between $500 and $1,000.
• If you have the opportunity, borrow a friend's camera or scanner and try it out - you may find that you need better quality than his/her camera can produce, but at least you have a baseline. The sales folks at the computer stores can often give you a demonstration - very handy if you are fairly new to the world of digital cameras or scanners.