using an alias

I have submited http://peakstudios.com as a multimedia company. I have made a site http://business-cards.peakstudios.com this site is specific to business cards can I submit it for a directory listing in it's own area or do I need to buy a domain name for it rather than using an alias.

Thank You for all your help.
Quince Wyss

You generally get one listing for the company only, in the best matching category for the company as a whole, it doesn't matter how many URL's / web sites you create.