Document Library Explorer 1.0 for SPS et WSS
Take control of your SharePoint document libraries. Document Library Explorer 1.0 is a fully featured web part to provide intuitive and simple, yet powerful enhancements to the document library user interface.
Introducing the first web part to provide treeview navigation and drag and drop maintenance of files and folders!
And in English on The Web Site of the French Club SPS with screen shoot:
Copying Lists Between Sites (SPS2003) and tools ... SPS DocumentMover
EROL MVP SPS