Microsoft's "Flash-killer," Silverlight released the third version of its rich media application platform, Silverlight 3, on the web yesterday. This morning, Microsoft is holding the official launch of Silverlight 3, which is a cross-browser, cross-platform, and cross-device plug-in for delivering media experiences and interactive applications for the Web. The first version was launched in 2007 and the second version was launched in September of 2008. In April, Microsoft reported 300 million downloads of Silverlight between September 2007 and April 2009, with an estimated 300,000 developers and engineers working off the Silverlight platform. The beta of Silverlight 3 was launched earlier this year. Now Microsoft is taking the beta off, and rolling out the full-fledged version of Silverlight 3 to the public. We had the opportunity to speak to Director of Microsoft’s Development Platform Group, Brian Goldfarb, about the new features of Silverlight 3 and the strategies behind the development of the new product. We also were able to talk to Scott Guthrie, vice president in the Microsoft's Developer Division, on camera about his perspective on the significance of Silverlight 3 and its potential to takeover main competitor Adobe's Flash (see video below). We've been able to compile a complete guide to SIlverlight 3 with all of its new features and the customers and developers who are using these features to launch innovative products. And Microsoft will also be demoing some of the real-time capabilities of Silverlight 3 at TechCrunch’s Real-Time Stream CrunchUp today.