The following worked for me using SSRS 2005, YMMV.
Create a URL with the following form:
The URL of the Report Server: http://MyServer/ReportServer
The report parameters:
- The first parameter is the URL of the report: http://MyServer/ReportsLibrary/MyReport.rdl
- rs:Command=Render
- rc:HTMLFragment=True
- rc:Toolbar=False
- rc:Parameters=False
Stick it all together and you get:
http://MyServer/ReportServer?http://MyServer/ReportsLibrary/MyReport.rdl&rs:Command=Render&rc:HTMLFragment=True&rc:Toolbar=False&rc:Parameters=False
Add an IFRAME to the web page using the above URL.