Yahoo! Sketch centers you on a map and then invites you to sketch a search zone with your finger [iTunes link]. Draw a circle around your current location, or an oval along the highway, or any geometric search parameter that suits you, and Yahoo quickly returns a list of restaurants in the area.
You can filter the search results by cuisine and cost, or just take all the results. When you make a selection, you can check out photos of the restaurant, get driving directions, and more. It's not Yelp, to be sure, but it gets the job done.
It's the most innovative way to search I've seen in a while, and it works quite naturally. If you have an iPhone, grab this app -- it's free.