I love it when very familiar user interfaces are used as business card designs. Here's a great one by Beasty Design.
Beasty Design's iPhone Business Card
Similar Designs:
Hired Hands' Textured Business Card
White Expo's Advertising Business Card
iPhone Monster's Business Card
I Draw Designs' Graphic Design Business Card
Murillo Design's Wooden Business Card
Designs By Elizabeth O'Brien Letterpress Business Card
Reactor's Cool Business Card
Business Card Design Idea Brainstorming
Frank Woll Designs' Letterpress Business Card