You can use CS3, Corel...whatever. If he wants full color cards just make sure you leave margin. You can do a google for a full color business card template, or I have on in a PDF if you want.

The possibilities are endless. Depends on what your dad wants. And finding a good printer....I got one of those too. And they are cheap. Not cheap by quality, just cheap because they mass run cards so you get a great price...about $25 for 500 full color d/s shipped to your door.