Apple will release its latest smartphone in the world's largest mobile market Saturday, just a week after officially launching its iPad tablet computer here.The company is also opening two new stores in Beijing and Shanghai this weekend, which will double its retail presence in the country.

Apple already has one store in each city and said it plans on opening 25 more stores in China by the end of next year.Similar to the high profile launch of the iPhone 3 in China last October, analysts say they expect much fanfare around the release of the iPhone 4, which will be available in Apple stores as well as at China Unicom outlets for customers with a two year contract, the company said in a press release.The 16-gigabyte version of the phone will cost 4,999 yuan ($745) while the 32-gigabyte will sell for 5,999 yuan ($895), the company said. [Read the full article]

Have you ever looked up at the sky, seen a plane zipping through the clouds and wondered, "Where the heck are those people going?"Plane Finder AR, which debuted last week and costs $2.99, lets iPhone users point their phones at the sky and see data about flights passing overhead.Among the data presented to users: How fast the planes are moving, where they're going, where they started, their elevation, the flight number and how far the aircraft are from the person's smartphone at exactly that moment.To accomplish this, the app employs "augmented reality" technology, which refers to an emerging -- and at times clunky -- category of smartphone apps that seek to overlay digital information on top of the real world.Augmented reality apps let people essentially use their phones as a lens through which to view what's going on around them. The apps switch phones into camera mode, so users see a moving picture of the nearby environment. [Read the full article]

Facebook's outage that shut down the site for many users Thursday was its worst since it became a worldwide social-networking powerhouse, according to an engineer for the site.In a blog post, Robert Johnson said an error in Facebook's automated system for fixing software problems made a problem worse instead of better."This is the worst outage we've had in over four years, and we wanted to first of all apologize for it," Johnson wrote.He said the outage lasted for about 2½ hours for millions of Facebook's half-billion users. It began about 2:30 p.m. ET.A Facebook spokeswoman said the issue was not related to the one from Wednesday, when problems with a third-party network provider shut the site down, or slowed it badly, for several hours. She didn't elaborate on the nature of Thursday's outage. [Read the full article]

Editor's note: Amy Gahran writes about mobile tech for CNN.com. She is a San Francisco Bay Area writer and media consultant whose blog, Contentious.com, explores how people communicate in the online age.(CNN) -- Cell phones have become one of the most ubiquitous hallmarks of life in the 21st century, but they aren't necessarily good for the environment.First of all, there are the materials. From plastics to the rare, powdery precious metal tantalum (mined primarily in Central Africa, where it's become implicated in local exploitation and violence and is now known as a conflict mineral), cell phone materials present a variety of environmental and even human rights issues.Then there's energy use. Smartphones are especially notorious energy hogs, with most models rarely getting more than a day of usage without some pretty drastic energy-saving strategies. [Read the full article]