Smartphones

The Samsung Galaxy S4 made its theatrical debut earlier this month, and the highly anticipated phone, which is packed with futuristic features, is now available for preorder on AT&T.

AT&T subscribers can get their hands on Samsung's newest Android device (16GB) for $200 with a two-year contract or $640 with a month-to-month plan. Head over to att.com/galaxys4 and enter in your information to preorder. Phones will ship on April 30 and arrive on or before May 3rd with two-day shipping.

T-Mobile has announced that the Galaxy S4 will be available on May 1, but the carrier has not specified whether the phone will be open to preorders or sold in retail stores on that date. Sprint, Verizon, and Cricket have also committed to carrying the latest Galaxy phone, and we'll keep you updated on the S4's availability and pricing with those carriers in the coming months.

The Samsung Galaxy S4, which runs on Android 4.2.2, is five inches tall and boasts the world's first full HD super AMOLED display. The phone has air gesture recognition and eye scrolling, and recognizes touch even if you're wearing gloves. Preview all of the phone's flashy features in this gallery and let us know if you'll be preordering Samsung's "next big thing."

Neglecting to clean your cell phone is a nasty tech habit to break this year. Cell phones have been proven to carry bacteria, germs, even feces. Yes, feces. If there's one new routine to create for yourself this Spring, it's keeping that smartphone shiny and clean. Your health will thank you. Check out a few of our tech-friendly tips to clean that gadget, below.

• Cleaning your touch screen smartphone is kind of like cleaning your LCD monitor — you don't want to use any harsh chemicals or, even more damaging, water. Using a tried-and-tested cleaner like iKlear ($21) will ensure you won't damage your phone's sensitive bits. Use the included microfiber cloth (or one of your own) and shine that baby up.
• If you don't want to spring for a special formula, a 40/60 alcohol-to-water mixture on solid phone parts and keyboards should be OK for your devices (use a damp cloth and/or cotton swab for small and hard-to-reach places). However you do not want to use any sort of alcohol, ammonia, or harsh cleaning agent on touch screens.
• If you're in a pinch and want to quickly rid your phone of dirty crevices and fingerprints, use a piece of Scotch Tape to peel away dirt and dust in between keys, and rid your phone of fingerprints. Perfect for when you're at the office (without a microfiber cloth), but unfortunately it won't help the germ situation.
• Serious germaphobes can ensure a clean device with the UV Cell Phone Sanitizer ($50), which wipes your device clean of 99.9 percent of strep, E. coli, salmonella, listeria, and H1N1 viruses in three minutes flat. Just drop it in once a day for germ-free surfing and calling.

In the mood to refresh your tech life? Here's nine more bad tech habits to break this Spring!

Mozilla, maker of the nonprofit Firefox web browser, is taking on iOS and Android with its own mobile operating system, Firefox OS. The company showed off the first commercial build of the Firefox OS at 2013 Mobile World Congress in Barcelona, Spain, and announced that the new "open web" OS will make phones for low-income markets more accessible than ever.

Mozilla's operating system is built on a brand new concept — the Firefox OS is based entirely on Open Web standards, and apps for the operating system are developed as an HTML5 application. Unlike iOS and Android development, mobile software engineers won't need to learn a new coding system for Firefox OS. They will be able to write apps in HTML5, opening up the system to more developers.

Think of Firefox OS apps as mobile-optimized websites that you would bookmark on the home screen of your iPhone. Instead of "native apps," like the kind you download from Google Play or the Apple App Store, Firefox OS apps are based on the web.

This affords developers the ultimate flexibility to design an interface uniquely suited for their customer base. Firefox OS phones will initially roll out to markets in Brazil, Colombia, Hungary, Mexico, Montenegro, Poland, Serbia, Spain, and Venezuela. Phone makers LG, Huawei, Alcatel One Touch, and ZTE are already planning on releasing devices with the new Firefox OS ecosystem.

Mozilla's new mobile ecosystem, which is positioned to make smartphones more accessible and affordable, may be a game changer for international markets. How do you think the nonprofit company will affect the mobile phone market?

Having an unlimited smartphone plan for $19 per month sounds too good to be true, but one North Carolina carrier, Republic Wireless, is providing just that.

The reason why the company is able to provide such low pricing is the technology called hybrid calling, which allows users to use WiFi to text, make calls, and surf the web. You'll still have access to a cellular network (Sprint) for free, in case you don't have access to wireless Internet in certain places, but the default network would be wireless.

Currently, the only phone the firm is offering with its plans is an Android smartphone, the Motorola Defy XT. There are also only two plans being offered right now: one in which you pay $249 for the phone, then $19 per month, and another which you pay $99 for the phone, then $29 per month. You apparently get unlimited data, voice, and texts, all with a 30-day money-back guarantee if you're not happy with it.

AllThingsD recently took the phone out for a test drive and here's what they found.

Pros:

• The low, low price: You simple can't beat the low price of the unlimited data Republic Wireless plans. Many carriers charge you around $70 to over a $100 for unlimited data usage plans.
• There's a backup: If there's no WiFi network around, you can rely on the Sprint cellular network without extra charges.
• Does its job: Texts worked normally, according to the tester, and the call quality, web browsing, and app service were adequate.

Read on for the limitations of this phone.

Shopping for mobile devices is a curious thing — why do carriers offer data-only plans for the iPad that are cheaper and more flexible than typical plans for smartphones? Turns out that subscribers pay a hefty fee for standard unlimited talk and text and are often trapped into two-year contracts in order to afford their smartphones.

Device plus data packages are usually offered on a month-to-month basis with no contract. It just makes sense. We've compiled a guide to going rogue and getting a data-only plan, with details on how much you'll save, which carriers offer data only, the essential apps you'll need for free talk and text, and what the downsides are.

How Much Will I Save?

Let's take a closer look at Verizon: purchase an iPad, and data will run you $30 per month for 4GB with no contract. The same month-to-month plan for an iPhone (with required unlimited talk and text added on) is $70 per month — that's $480 more per year!

Data-only plans run from as low as $25 per month to as high as $70, but the average user (emailing, web browsing, Instagramming, some streaming) will pay about $35.

Read on to find out which carriers currently offer data-only plans, the available devices, apps you'll need, and what the downsides to cutting talk and text are.