A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
Basically you'll want to start by setting your PPT slide size to match the size of the card you want to create, then create your design as two separate slides, one for the outside of the card, one for the inside.
Unless your printer can do two-side printing, you'll need to run the paper through the printer twice, once for each side. A bit of testing will show you which way you'll need to turn the paper between slides to get the outside and inside properly oriented to one another.
Let us know if you run into any specific difficulties and we'll try to help.