OpenForPSCmdlet helps debugging your Cmdlet binary module writing C# or VB.
visualstudiogallery.msdn.microsoft.com
After install this VS extension, you can right click "Open for PSCmdlet" in your Cmdlet class.
Then run build and open PowerShell console with Importing your Cmdlet module.
In the latest version, VS attaches PowerShell console process and you can debug directly.
This extension is opens source. Your comments and requests are welcome.