I'm desperately searching for a tool allowing me to copy documents with their old versions from a SharePoint 2003 to a SharePoint 2007 site.
Do you know about any simple (and preferably free) tool which does this?
This may be too late for you, but I needed to migrate from a SharePoint 2003 site to a SharePoint 2007 site and keep not only versions, but also the file metadata from all of the document libraries. The official methods of migrating or upgrading failed, so I ended up writing a tool that must run on the destination SharePoint 2007 server, but can copy from the 2003 server all lists and document libraries with metadata and version intact. It's available with source at http://sourceforge.net/projects/splistcp so feel free to use and improve it.