TripIt helps you get your trip research and itineraries under control and into one place for easy access. You can even book restaurants, theater tickets or activities from within the site. Visit TripIt
Weatherspark lets you look up years of past weather data to see what weather is really like during certain times of year. It can help ensure that the highlight of your vacation isn't cable re-runs. Visit Weatherspark
AirBnB connects people who have space to spare with those looking for a place to stay by letting you rent lodging directly from locals. It's a great way to save money and have a unique travel experience. Visit AirBnB
The GasBuddy app searches prices at gas stations near your current location. The results are mapped so you can find the closest and cheapest refueling options. Download GasBuddy
Using a smartphone abroad? Onavo can help you avoid a mammoth phone bill. It cuts down on the downloading required to use your favorite apps with cloud technology. Download Onavo
WikiMe for iPhone indexes Wikipedia articles about local points of interest, and then uses GPS and geotagging to show you those articles when you're nearby. It's like a pocket tourguide. Download WikiMe
Vayable lets you hire a local to give you a guided tour of his or her home city, on a subject your guide knows and loves. Tours cover everything from sailing excursions in CA to pizza tours of NYC. Visit Vayable
Postagram lets you send postcards made from your own photos right from your cell phone. For just $.99 it's a super-easy way to share vacation pictures before you even get home. Download Postagram