.NET

Oxygene for .NET
a.k.a. “Echoes” — supports, .NET, Mono, Silverlight and WinRT
Oxygene for .NET, also referred to as "Echoes", is the flavor of Oxygene that creates applications for the Common Language Runtime (CLR). Most prominently this includes the Microsoft .NET Framework, but also extends to WinRT (the new API layer for Windows 8 and Windows RT applications, Windows Phone, Silverlight and the open-source Mono framework, which brings the CLR to Mac OS X, Linux and a range of other operating systems.
The CLR is designed to be language independent, making Oxygene a first degree citizen next to Microsoft's C# and Visual Basic.NET languages. In fact, Oxygene is the most prominent and most widely used non-Microsoft language for .NET.
Framework and Technologies
On top of .NET and the CLR, a wide variety of technologies are available for building great applications. .NET comes with an extensive Framework Class Library (FCL) of over 10,000 classes and types that are instantly usable from Oxygene, not to mention a wide range of open source and commercial third party libraries that are available and work seamlessly with any CLR language, including Oxygene. (RemObjects Software even provides a few of its own, such as Data Abstract).
Depending on your target platform, the CLR provides a choice of GUI frameworks for creating powerful native applications, including WPF and WinForms for Windows Desktop apps, XAML for WinRT/Metro and Windows Phone apps, and XAML/Silverlight for creating plugin-based web apps. Oxygene supports all of these frameworks and their toolchains natively and out of the box.
On top of that, the .NET Framework also contains classes for just about any business need, from internet communication to working with XML files, from database access to encryption, and so on.
The Frameworks section of this website gives you starting points for these topics.