One of the problems using Silverlight on SharePoint 2007 is how can we add a Silverlight control in the SharePoint site?
A quickly and simple solution that i found to do it is the SPSilverlight web part, a web part that allows you to add a Silverlight control to SharePoint.
The only configuration that you need to known is the path where the XAP file is stored in SharePoint (on the layout’s folder, on the library…).
To use this web part you need to install the following package:
http://spilverlight.codeplex.com/Release/ProjectReleases.aspx?ReleaseId=35120