Facebook, together with over 50 mobile operators in 45 countries around the globe, have just launched the new website 0.facebook.com. It brings all the key features of Facebook to people’s mobile phones, loads fast and comes for free. Yeap, zero data charges! But there’s a tiny little catch.

More than 100 million people are using Facebook’s services from their mobile devices but now, a lot of them will be able to continue doing that without having to pay for data charges.

The new site is designed to be faster than both Facebook’s core Web site and its traditional mobile site, but still offer the same features, according to the company’s blog. Users can view content, update their status, and keep in touch with their Facebook friends.

But the new mobile site won’t display photos by default. Users will have to click on a link to view any photo, and that’s where the free ride ends. Viewing a photo turns the data charges back on, as does clicking on a link to a third-party Web site. But a confirmation message will pop up notifying users that they may be charged if they leave 0.facebook.com.

The new mobile site will be available only in select places, including Brazil, Denmark, Greece, Hong Kong, India, and Turkey, and only through certain mobile carriers. But Facebook is promising that it will soon debut in other countries and with more carriers, including mobile operators in France and the U.K.

Mobile users outside of the supported countries and carriers can still access the Facebook through its standard mobile site or its site for touch-screen devices, though of course, data charges would still apply when going through a mobile carrier.