I'm always looking for DICOM tools to use in practice and for training purposes. After some searching on the web I've located some links to free DICOM tools that could be usefull. I did not test them all so I'm not sure of the quality of the tools, but here they are (if you notice broken links or tools that are not free (anymore) please let me know).
DCMTK is a collection of libraries and applications implementing large parts the DICOM standard. It includes software for examining, constructing and converting DICOM image files, handling offline media, sending and receiving images over a network connection, as well as demonstrative image storage and worklist servers.