http://www.melissaclifton.com/tutorial-comicbook.html
What I would like to do in PSP 7. Click on the "Gallery" button to see the actual photos used to create the black and white vector images.
http://www.digi-portraits.com/
Everything in the other responses are right on the mark...after looking at the site I am sure they are produced in Either Photoshop or Adobe Illustrator, as they have the ability to "stroke the path" with a brush, which is what gives the lines in some of the illustrations a wispy fading look, unfortunately we PSP users don't have that option, but with some creative line making and careful use of the eraser you can produce similar results with PSP using the pen tool...There is an excellent tutorial written by Melissa Clifton you might be interested in...
http://www.melissaclifton.com/tutorial-comicbook.html
While it is written for photoshop, it is an excellent guide to learning to do line art. Here are some examples of work I have done with the pen tool in PSP.
