.NET Framework 3.0

When speaking to developers about WinFX one question that repeatedly comes up is, “WinFX sounds great, but what happens to .NET?” .NET Framework has become one of the most successful developer platforms in the world.
The .NET Framework has always been at the core of WinFX, but the WinFX brand didn’t convey this. The WinFX brand helped us introduce the incredible innovations in terms of Windows Presentation Foundation (WPF), Windows Communication Foundation (WCF), Windows Workflow Foundation (WF) and the newly christened Windows CardSpace (WCS) formerly known under the codename “InfoCard.” The brand also created an unnatural discontinuity between previous versions of our framework and the current version.
With this in mind we have decided to rename WinFX to the .NET Framework 3.0. .NET Framework 3.0 aptly identifies the technology for exactly what it is – the next version of our developer framework.
The change is in name only and will not affect the technologies being delivered as part of the product. The .NET Framework 3.0 is still comprised of the existing .NET Framework 2.0 components, including ASP.NET, WinForms, ADO.NET, additional base class libraries and the CLR, as well as new developer-focused innovative technologies in WPF, WCF, WF and WCS.
The .NET Framework 3.0 will still ship with Windows Vista, and will be available down-level for Windows XP and Windows Server 2003 as planned. This change doesn’t affect in any way the ship schedules of either Windows Vista or the .NET Framework 3.0 itself.

C# 3.0: An Introduction

.NET 3.5

With the release of .NET 3.5 is Language Integrated Query (LINQ).
LINQ essentially is the composition of many standard query operators that allow you to work with data in a more intuitive way regardless of the data source.

You can query in-memory collections, Relational Data and XML.

For an introduction to LINQ goto : .NET 3.5 LINQ