Android is a smart phone operating system (OS) developed by Google. Android was originally developed as a response to the iPhone's dominance of the smartphone market, much like Palm's WebOS and various forms of Windows Mobile, Nokia's Symbian, and BlackBerry's operating systems.

One of the major differences between Google's Android and its competitors was the decision to make the operating system platform neutral, which means that Android can be run on a large variety of different smartphones. Google has also made Android open-sourced, so if you have the skills and inclination you can change and improve the software. This makes Android very appealing for individual web developers. As mobile phones bridge the gap between simple telephone functions and those traditionally found on computers, the struggle for a piece of the rapidly growing market has intensified.

To understand Android, it's important to highlight the differences between it and other platforms running on smart mobile phones. Android is based on a operating system called Linux, a free and open source OS developed many years ago for mainframe computers. Linux has evolved into a personal computer platform as well as the bones of several mobile devices like Nokia's N-series of Internet tablets. In Android, Linux forms the kernel of a mobile phone operating system. Using Linux like this means that the base of the program is open sourced, so anyone can use and modify it to suit their needs. This is a fundamental change from the types of operating systems offered by other companies.

Using Linux also creates a flexible environment for updating and upgrading the phone's operating system. In the several years since the iPhone has been released, it has gone through only three major revisions. In the two years since Android debuted it has already gone through two major revisions, demonstrating the flexibility and responsiveness of the upgrading process.

All of this takes place below the surface of the Android platform and is generally invisible to the user except for performance enhancements and new features. To the user, Android is the interface through which they use their phone. Like computer operating systems, Android can run on any compliant piece of hardware. The same operating system runs on Motorola, HTC or Samsung phones, as well as other pieces of mobile hardware. Some phones run tailored versions of the operating system optimized for the specific phone. Motorola's Droid is an example of this, as is the Google branded Nexus One. All of these phones have the same operating system running them, though their performance may vary based on the hardware.

All this technical talk is well and good, but what does it mean for phones using Android? Well, Android is a Google project, so it syncs with all of the usual Google applications through the Internet. Gmail, Google Calendar and all the other Google services are integrated into the phone's operating system. But the Android also handles competing services for email and other functions, including MS Exchange for emails. This is in contrast to the iPhone which routes all of the syncing processes through iTunes. Android also has an impressive graphical interface allowing you to control the contents of your handset in a manner similar to the iPhone's touchscreen. Early versions of the OS didn't support multi-touch, meaning that the computer could only recognize one contact point on the screen, but later versions have provided multi-touch support as well as gesture recognition functions.

Android also features a complete marketplace, much like the App Store found for the iPhone. Applications developed by Google or by third parties can be downloaded onto the phone. Apps come in free and paid versions and at the time of this writing nearly 60 percent of the the Android Market's 27,000 apps were free. While Android Market is still significantly smaller than Apple's App Store, which currently boasts 140,000 applications, it has been a component of the Android experience from the start of the operating system's existence. Less than six months ago Android Market had only 10,000 applications. Coupled with the open source nature of the Android operating system, the number of applications is likely to increase very quickly.