oh boy, shameless plug time! yelp is a great desktop experience, but if you've got an iphone give graffiti a shot:
http://www.graffitigeo.com. it's a bit more fun to use than urbanspoon and goodrec with the mobs and badges. no registration or anything like that needed. you can see my profile here as an example:
http://graffitigeo.com/jaredp.s. we do not pay anyone to write comments or create the walls.