Microsoft Silverlight is a powerful tool for creating and delivering rich Internet applications and media experiences on the Web. Silverlight 5 builds on the foundation of Silverlight 4 for building business applications and premium media experiences. Silverlight 5 introduces more than 40 new features, including dramatic video quality and performance improvements as well as features that improve developer productivity.
Silverlight offers a flexible programming model that supports AJAX, VB, C#, Python, and Ruby, and integrates with existing Web applications.
Silverlight works on all major OS's plus all major browsers, including Firefox, Google Chrome, Safari, and yes, Internet Explorer.