The guidgen that is tools to generate GUID. I often used it to develop COM.
In the Visual Studio 6.0, the Visual Studio included the guidgen. However, the VS.NET dosen't include it but Windows SDK includes it. Therefore I forget and lose it sometimes.
Then I developed the guidgen web application and released it here: http://labs.makotokw.com/guiden/ "guid web application" use ExtJS and BlzGuid.js.
Please use it! And let me know if you found any problems!