iOS: If you have a Twitter account and an iPhone, iPod touch or iPad, Forkly can help you find local restaurants or bars to try and what you should eat and drink when you get there so you don't wind up ordering something awful.
Forkly wants to help you decide what's worth ordering, not just where to eat. Use the app to search for restaurants, and select one to see what other members have snapped photos of or rated highly at that restaurant. When you've finished a meal, submit your own review of what you ate (and photos if you took them,) share it on Twitter or Facebook, and pay it forward by letting others know what's worth trying (or not worth trying, depending on your experience.)
Forkly is a bit like previously mentioned Foodspotting, except it's limited to iOS devices. Regardless, the Forkly app is popular on the iTunes App Store, and gives users incentives to participate through leaderboards and "influence" points for people who share frequently. The service is free, and uses your Twitter account to log in, so you'll need one to use the app.