A year old and the Apple App Store has already witnessed over 1.5 million application downloads, from around 65, 000 odd apps. And coupled with the sales of its sibling, the iPod Touch, iPhone has sold 40 million units till date. So what makes them tick? - is it the sleek design or the operating system that runs the fabulous apps?For an answer, we took a quick look at the features of both the iPhone 3G S as well the operating system OS 3.0. iPhone 3GS offers a 256 MB RAM as opposed to 128 MB available earlier, has more battery life and new features like video recording and a better camera (3.0 MP) for still photographs. Considered more evolutionary than revolutionary, OS 3.0 is proving to be a compelling upgrade for the average iPhone user, with capabilities such as cut, copy and paste; system wide searching; a wider virtual keyboard; and MMS, which allows users to send photos and videos directly to other phones without using email.The other new features of OS 3.0 are facilities like moving an icon across screens with one continuous swipe, instead of stopping at each screen. And there are two more screens to house icons. You can also synchronize Notes with your PC or Mac now! Finally, you can actually locate a lost iPhone on a map on any computer. Simply send the iPhone a message instructing how to return it to you, and cause it to emit a beep, even if the sound is turned off. (To avail this facility, you have to subscribe to apple's $99 a year MobileMe service)Our suggestion: A combination of the iPhone 3GS and the new operating system 3.0 is the best possible iPhone combo. But, for many users, the OS 3.0 may be enough to give them the rich experience that they have been looking for, without purchasing the iPhone 3GS.The bottom-line is that the operating system is the heart of the iPhone experience. With innovative rich mobile apps like WorldView, which allows you a view across the world through 6,000 webcams, the world of rich mobile applications can only grow bigger.And the best part is that if you hit the jackpot, there could be millions downloading your application. So do you have any groundbreaking ideas that will rock the App Store? Talk to the experts at Web Spiders and watch your dream app unfold.