GrayWolf!

ILSpy is the open-source .NET assembly browser and decompiler.

What's Cool about dotPeek?Decompiling .NET 1.0-4.0 assemblies to C#Quick jump to a specific type, assembly, symbol, or type memberEffortless navigation to symbol declarations, implementations, derived and base symbols, and moreAccurate search for symbol usageswith advanced presentation of search resultsOverview of inheritance chainsSupport for downloading code from source serversSyntax highlightingComplete keyboard supportdotPeek is free!

JustDecompile is a stand-alone, free decompiling tool which converts assemblies into source code.

.NET Reflector is a class browser and analysis tool for .NET. It allows developers to navigate, search, disassemble and analyze .NET components.

Created by Daniel Pistelli, a freeware suite of tools including a PE editor called CFF Explorer and a process viewer. The PE editor has full support for PE32/64. Special fields description and modification (.NET supported), utilities, rebuilder, hex editor, import adder, signature scanner, signature manager, extension support, scripting, disassembler, dependency walker etc. First PE editor with support for .NET internal structures. Resource Editor (Windows Vista icons supported) capable of handling .NET manifest resources. The suite is available for x86 and x64. »

Zeta Resource Editor is a free application that enables you to edit standard Microsoft .NET string resources from multiple different resource files together inside one single data grid.

Free Zend Guard decoder, Free Java class decompiler, Free Adobe Flash swf decompiler, Free .NET (Dot NET) decompiler