JetBrains has released dotPeek 1.0 a free-of-charge .NET decompiler and assembly browser.
dotPeek decompiles any .NET assemblies based on .NET Framework 1.0 to 4.5 into equivalent C# code. It supports libraries (.dll), executables (.exe), and Windows 8 metadata files (.winmd). Which is of course great news if you are trying to figure out how something works or make a modification - but not so reassuring if you have code you want to protect.
If source code is available, dotPeek can identify local source codebased on PDB files, or fetch source code from source servers such as Microsoft Reference Source Center or SymbolSource.org.
dotPeek lets you search to find where particular code symbols are referenced. Find Usages displays all usages of a symbol (method, property, local variable etc.) in its Find Results tool window where you can group them, navigate between them, and open in the code view area:
It also allows provides a Go to File Member facility to enable you to navigate to member of a file representing a decompiled type:
For users of JetBrains ReSharper, dotPeek provides ReSharper-like navigation and search, code insight, and keyboard shortcuts.
This video gives a quick walkthrough of dotPeek's in action:
dotPeek is available as an .msi installer for easier version management and as a .zip archive if you prefer to keep it in a location shared between machines.