With so many cell phones shipping with organizers, Web browsers, and e-mail capability, the line between typical clamshells and smart phones has blurred. So what defines a true smart phone, and which are the best ones to buy? Read on to find out.

 

Smart Phone OS (Ability to Add Third-Party Apps)
Generally, a smart phone will have a robust operating system--one that powers all of the included applications and allows users to easily add new applications from a number of third-party developers. If, for example, you're on Handango.com and you see something that's designed for Windows Mobile, it should just work. You purchase the app and then sync it over to your device using USB. Other smart phone OSes include Palm, BlackBerry, and Symbian. Whether you're looking to get up-to-the-minute travel info on your Samsung BlackJack (WorldMate), send a few instant messages to your buddies on your BlackBerry Pearl (IM+), or watch your home TV from anywhere (SlingPlayer Mobile), you'll be able to choose from hundreds of programs. The best part is that a lot of these apps can now be downloaded over the air right to your smart phone.

 

QWERTY Keyboard 
Generally, smart phones are used for heavy e-mail and text messaging. That's why a full QWERTY keyboard comes in so handy. With the exception of the Pearl, which sports a capable SureType setup--slightly smaller than a full QWERTY but with fewer keys--every smart phone here has a full QWERTY. Look for a keyboard layout that's widely spaced enough for your fingers and that offers enough tactile feedback so that you never have to guess whether or not you hit a key. One overlooked feature is a keyboard backlight, which is great if you use your device to check e-mail or look up quick info online in dark places, like a dimly lit restaurant.

 

E-mail and Attachment Support
Constant e-mail access is one of the pillars of smart phone use. All smart phone operating systems include dedicated e-mail applications. Windows Mobile has Outlook Mobile; Blackberry has its famous push e-mail solution that works with both the company's BlackBerry Internet Service and BlackBerry Enterprise Servers; Symbian OS devices, like the Nokia E62, support Good Mobile Messaging, BlackBerry Connect, Nokia Intellisync Wireless E-mail, and Microsoft Exchange; and Palm OS devices support Exchange as well as POP and IMAP clients. Just as important is attachment support.

 

Unlike the most regular phones, smart phones will let you quickly preview that Word doc, Excel spreadsheet, or PowerPoint file. And an increasing number of smart phones support PDF files. Editing attachments is not always a given, however. For example, Windows Mobile 5 Smartphone Edition devices like the MOTO Q let you view attachments but not edit or create them, while more robust (and more expensive) Pocket PC Edition devices like the Cingular 8525 can edit Office docs. But the beauty of smart phones is that you can download software to address many built-in limitations. Documents to Go for Windows Mobile 5 and 6 Standard ($29.99) will let you make edits on your smart phone while retaining the formatting.

 

Organizer
You can sync your contacts and calendar over the Web to regular cell phones with only a little bit of effort, but the ability to edit them on the fly is one of the key features of smart phones. The idea is that many users will be on the road, thus requiring a device that can easily manage appointments. Microsoft's Outlook Mobile for Windows Mobile is a proven contender in this arena, but all major smart phone operating systems sync with Outlook on the desktop over a USB connection. This includes your contacts and calendar but also tasks and any memos or notes you take on the go.

 

Full Web Access
Web access is an absolute necessity for any smart phone. Just getting e-mail is great, but when e-mail messages contain links, you're going to need fast data access to check them. The ability to surf to virtually any site using an HTML browser is what separates smart phones from most regular cell phones. You can't go to YouTube and start streaming videos, but you'll be able to access most of the sites you visit on your PC. You'll also be able to quickly save your favorite sites as bookmarks and visit them with just a couple of clicks the next time you're online.

 

Do you need a so-called 3G connection? It actually depends on the operating system and the hardware. In general, we prefer EV-DO (Sprint and Verizon Wireless) and HSDPA connections (Cingular), but EDGE (Cingular and T-Mobile) is fine for such devices as the BlackBerry Pearl, BlackBerry 8800, and Palm Treo 680. That’s because the included browsers are very efficient and load pages quickly even on slower data networks. On the other hand, we wouldn’t recommend a Windows Mobile smart phone without a 3G or Wi-Fi data connection, because Internet Explorer tends to be sluggish.

Full-Blown Multimedia
Regular cell phones can now download full songs over the air and tune in to live TV on the go. But smart phones have some unique multimedia perks you won't find on other phones. For example, all Windows Mobile devices can play secure WMA audio files out of the box, which means you can purchase music from or subscribe to an unlimited to-go music service from an online store like Yahoo Music, Rhapsody, or Napster. You can also use a Windows Mobile device to watch TV shows you've recorded using a Media Center-enabled PC.
 
Windows Mobile devices don't have all the fun. Services like Orb allow you to stream your tunes from your PC to your smart phone running Palm OS, Symbian, or Windows Mobile. (This service works with some regular cell phones, too). And SlingPlayer Mobile allows Slingbox owners to watch their live and recorded TV content on Palm OS, Symbian, and Windows Mobile devices. Plus, there are tons of streaming music services available for smart phones that leverage the power of the devices' always-on Internet connection, including MunduRadio and Pocket XM Radio.
 
BlackBerry devices have traditionally been buttoned down, but new models like the Pearl and 8800 come with built-in media players for enjoying your favorite tunes, pictures, and videos on the go.

 

Now that you're fully armed with all the information you need, here are our top smart phone picks.