Yelp. Ah, my favorite restaurant guide. Yelp has a wonderfully elegant interface for browsing restaurants nearby your current location, and it's packed with user reviews - some useful, most entertaining. It also has Monocle, an augmented reality mode that points out local points of interest by overlaying them on live video of your surroundings through the camera. As I've mentioned before, it's a tad gimmicky right now, but your grandkids won't (legally) be able to leave their cyberpods without something very much like it.
Urbanspoon. This one has been around a while, but it's still a great way to explore the culinary personality of a new city. You've got three slot machine-like wheels to spin: location, cuisine, and price. Lock one or more down and then shake your iPhone to get a random recommendation. And Urbanspoon has its own augmented reality mode too now, called Scope.
Shake 2 Find. If you enjoy shaking your iPhone to get dining recommendations, you'll also want to install Shake 2 Find, which uses the Mashspots points of interest database integrated in Google Maps. The basic concept: Shake 2 Find shows you four nearby restaurants in the designated dining style. Shake your phone, and it'll move on to four establishments in the next cuisine. Like the other apps, Shake 2 Find lets you see driving directions and other details, but sorry - no augmented reality here.