There are thousands of applications for smartphones, but which ones are actually helpful for travelers? Here are a few that can really come in handy… or are just downright funny.

One application called Taxi Magic works free for both the iPhone and Blackberry.

It gives you a list of the local cab companies and allows you to book a cab to pick you up, and pay via credit card—all without even having to make a phone call.

Or check out OpenTable, which has free mobile applications for the iPhone, BlackBerry and PalmPre. You can find nearby restaurants, make reservations, and even invite your friends to join you.

Another app called MetrO works free for the iPhone, and provides you with public transportation options for 350 cities around the world.

Just download the city guide, and search for your route.

And instead of using the usual hotel booking sites on your phone’s Web browser, a better option is the HotelPal application, which lets you book a hotel room while you’re on the go.

And then there’s this one, which falls under the category of “You can’t make this stuff up.”

It’s called Sit and Squat, free for the iPhone and BlackBerry, which tells you the locations of nearby bathrooms—and in some cases, includes pictures.

Get more information with Travel-Friendly Applications for Smartphones.

Looking for more advice? Click here for more Daily Travel Tips.