Directing A Parked Domain To A Sub Directory

I've got a website, we'll call it MainDomain.com. I created a specialty site in a sub-directory. We'll call the sub-directory Widgets. I want a different domain to point to that sub directory. We'll call the new domain WidgetWorld.com My webhost will allow me to park WidgetWorld.com at MainDomain.com. However, if someone goes to WidgetWorld.com, it would pull up the index page for MainDomain.com. How can I use PHP to detect if the visitor wanted MainDomain.com (and display MainDomain/index.php) or WidgetWorld.com (and then display MainDomain/Widgets/index.php). Thanks, Jeff Gannaway ___________________________________________________________ Find the right art print for your home. * Search by artist, color, art style and subject. * Preview the art prints against your wall color. * Specializing in contemporary, abstract and African   American art. * Every day discounts on thousands of fine art prints. PopStreet.com is your avenue to art. http://www.popstreet.com ___________________________________________________________