As Brian said, Edit Site for 2003 has not been released yet.
However, I use the Project Server Sample Database Restore Utility to do the
same thing the Edit Site Utility did. You may need to install this again if
you didn't install the Sample Database
1) Just restore the Project Server database and not a second WSS instance.
2) Restore the Sample Database or point to one of your own.
3) Then go into the database and point to your existing WSS installation,
recreate the subwebs, create a new OLAP Cube, and modify your Portfolio
Views to point to the new OLAP cube.
NOTE: You cannot restore a WSS database to the same server to restore the
subwebs because of the subweb GUIDs stored in the WSS database. So you
either need to restore the WSS database to another WSS Server or just delete
the existing subweb entries in PWA and create new subwebs for the new
instance.
I am successfully hosting many, many instances of Project Server 2003 using
a single WSS instance VERY successfully in Terminal Services and Citrix
hosting environments.