i dig the vector style art too. You can do it in Photoshop but if you have a vector graphics program like Illustrator or Xara you might as well use that cuz you'll end up with a true vector piece of work.
The Photoshop technique is just basically tracing on top of a photo different color areas with the pen tool. Here is a tutorial,
http://scudworkz.net/psmisc.php?id=vi , horrible job the guy did but the technique works if you have the time and patience. Tablet would definitely help.
It would be a cool plugin for Photoshop if u could just hit some buttons and turn photographs into vector looking art.