You can create business cards using Word templates and print them using Avery business card stock (found at Staples, Office Depot, etc.)
You should have your name, address, e-mail address and phone number on the card. This allows interested people an easy way to contact you.
You might consider scanning some of your work and reducing it down to card size to make your card a little more creative than just a black and white image. (That is if you work would allow that and you have a good color printer.)