I have noticed that lately we have many question regarding upgrading from Project Server 2003 to 2007 in the discussion Forum.
Upgrading is not easy, especially if you have used the Project Workspace in 2003.
Microsoft has an upgrade path and documented it. Check out this link here:
You can download the books:
Migration for Office Project Server
I know lately my blogs seem to be full of links, but hey, why would I want to recreate the wheel right :)
Till next time