I still have a small list of things to get working on wssdemo.com since migrating to the W2K8 Hyper-v platform. Today I managed to tick one off the list.
The SilverlightPart web part would give a 403 error whenever I tried to edit the web part properties. The Sysinternal Process Monitor is a great tool to find out what the w3wp was trying to access under what credentials. Because I have been trying to stick with Installing SharePoint Server 2007 by using the least privilege method (http://technet.microsoft.com/en-us/library/cc298465.aspx ) there is a bit more work in getting some things to work, especially 3rd party solutions.
In this case it was the NTFS security on the ClientBin directory which the web part property panel was trying to 'List folder contents'.
You can see the demo page here http://www.wssdemo.com/pages/silverlight2.aspx
It must be about time for the S+S Blueprint source code to be released (Paul)...
First off, Silverlight 2.0 is still beta so you should not install it on a production server, but for those who want to throw caution into the wind (it will be blown back in your face like me), here are the steps I went through for a non-development environment (i.e. no Visual Studio 2008 installed).
If you have tried to get this working before reading this post and just got a blank web part then step 5 is probably the solution.
If you just install the Silverlight BluePrint samples onto a SharePoint Server, they will not work because the following dependencies must be installed:
Perform an IISReset and you should now be able to add the SilverlightPart (1st demo from http://www.ssblueprints.net/sharepoint/) to a page. If you get a blank web part, step 5 above fixed this for me, if not it appears the only option is to recompile the web parts in VS 2008 (a bit tricky if you don't have such a development server).
Sample page hosting a Silverlight 1.0 Hello World XAML demo http://www.wssdemo.com/pages/silverlight2.aspx?PageView=Shared
The other samples require AJAX support so you will have to install ASP.Net 3.5 make major changes to your web.config file. I'll post steps for doing this on a non-developer SharePoint platform soon.