If your application is working with the registry frequently mostly while creating installer and you need to dynamically monitor your registry then you can use a tool called RegMon for Windows v7.04 . This tool is very helpful for viewing the registery...

If you are developing .net applications such as managed windows services, managed Add-Ins for MS Office or Interope application such Deskbar search etc.. and want to debug output without attching debugger or in production enviroment remotely you can use...