The Reflector Add-In for Visual Studio .NET is now being maintained in the .NET Reflector Add-Ins GDN Workspace. This has the huge advantage that for every new build of .NET Reflector the add-ins will be compiled and updated. Although the add-ins might keep working when you use Reflector's 'Check for Updates' feature - it is highly recomended that you download the latest add-ins.
In the latest build of the Visual Studio add-in I have fixed one of its most anoying shortcomings. In previous builds you were required to launch Reflector using the 'Addins/Reflector' menu before using any of the Reflector options. In the new build Reflector will be launched when you first use any of the Reflector related functionality. If you wanted to decompile some Visual Basic source into C# you could just select 'Reflector.../Decompile to C#'. 'Synchrinize Reflector' on the other hand keeps your existing view and only synchronizes Reflector (it is desinged to work in a similar way to 'Synchronize Class View').
You can download the latest add-ins from here. Make sure you unzip them into the same directory as 'Reflector.exe' (if you don't the installer won't work!). To install the add-in simply double click on 'Reflector.VisualStudio.exe'. This will install the add-in and fill Visual Studio with Reflector related functionality. It is a good idea to close all instances of Visual Studio before installing any add-ins.
If you have any problems, questions or ideas please comment here or in the workspace. If you find a bug then please use the bug tracker. There is a know issue if you close Visual Studio without first exiting Reflector. Visual Studio will forget Reflector's tool window locations. To avoid this simply exit Reflector before shutting down Visual Studio. Nothing bad will happen if you don't.