( CNN ) -- Social-networking giant Facebook has entered the check-in world . Facebook executives on Wednesday announced the launch of Facebook Places , which -- similar to services such as Foursquare and Gowalla -- will allow people to use the GPS on their mobile phones to let friends know exactly where they are . Facebook Places is available immediately in the United States through the latest version of Facebook 's iPhone app and , for other advanced mobile phones , through the company 's site for advanced mobile devices , executives announced at Facebook 's headquarters in Palo Alto , California . Users who wish to announce their location to their friends on Facebook would tap a `` check in '' button to see a list of places nearby , and then choose the place that matches where they are . `` After checking in , your check-in will create a story in your friends ' News Feeds [ on Facebook ] and show up in the Recent Activity section on the page for that place , '' Places product manager Michael Sharon wrote on Facebook 's blog . What do you think of the new feature ? Facebook staff also said the feature will be useful not only to let friends know where they are , but also to learn if their friends are nearby at the same time , and to write down what they are doing at the location and what they think about it -- creating a trail allowing friends to see what the writer did there days or even years ago . When users check into a place , they also can `` tag '' any Facebook friends who are with them , essentially letting other friends know that the person is there , too . To cut down on the potential for users to falsely tag friends to a place , people can tag friends only if the taggers themselves check in to the location , too . Sharon , speaking during Wednesday 's announcement , said Places has other safeguards to address potential privacy concerns . First , check-ins will appear only to users ' Facebook friends as a default , and users can further trim the recipients list to specific friends . Users also can remove check-ins by phone or web at any time , Sharon said . Facebook said it would make Places available in other countries and on more mobile platforms soon . Facebook staff said the company planned to let Foursquare , Gowalla and other services enhance their current integration with Facebook . Executives with Foursquare and Gowalla were at Wednesday 's announcement in Palo Alto , previewing plans to ramp up how their users will announce their locations on the social-networking site . The past year has seen big growth in the relatively new mobile check-in space . Foursquare , which essentially made its debut in 2009 at the South by Southwest Interactive festival in Austin , Texas , was one of the combatants in a so-called `` Location War '' at this year 's festival , going heads-up with Austin-based rival Gowalla . Since then , Foursquare has become the clear favorite of the two -- and a darling of tech media , even as it looks for ways to turn a profit . Boasting a half-million users at the start of SXSW , Foursquare doubled that in about a month then needed only another three months to hit 2 million last month . On mobile apps like Foursquare , users `` check in '' at restaurants , bars , movie theaters or just about anywhere else they visit . The idea is twofold -- to let friends know what you 're up to , while racking up points and earning virtual badges in the application 's gaming element . The New York-based Foursquare has begun forging some corporate partnerships and some businesses have started offering discounts and other deals for users who check in frequently . Facebook , with its half-billion users , represents a massive potential user base for Places . CNN 's Doug Gross and Jason Hanna contributed to this report .
Facebook makes announcement at its headquarters on Wednesday . The company said it would be making a number of changes to the way it handles user data and that users will have more control over how their information is used. Foursquare , Gowalla and other services to enhance their integration with Facebook . Feature available immediately in the United States ; more countries to come .