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).
Orthanc aims at providing a simple, yet powerful standalone DICOM server. Orthanc can turn any computer running Windows or Linux into a DICOM store (in other words, a mini-PACS system). Its architecture is lightweight, meaning that no complex database administration is required, nor the installation of third-party dependencies.
MicroDicom is application for primary processing and preservation of medical images in DICOM format. It is equipped with most common tools for manipulation of DICOM images and it has an intuitive user interface. It also has the advantage of being free for use and accessible to everyone.
DicomCleaner is a free open source tool with a user interface for importing, "cleaning" and saving sets of DICOM instances (files). It can: Import files from a CD or the local hard drive or a shared network drive or any other media, with or without a DICOMDIR, Query and retrieve from remote DICOM devices, "Clean" the DICOM "header" of a selected set of instances, Blackout burned in annotations in the pixel data of the cleaned files, Export the cleaned instances to a folder with a DICOMDIR, which can be burned to a CD or DVD, Send the cleaned instances over the network to a remote DICOM device
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.