When I started working with DPM 2007 there were little or no resources out there. This has changed as there are more and more resources for Data Protection Manager popping up all the time. Microsoft has even added dedicated forums to DPM on TechNet, there are DPM MVPs now and more and more IT professionals are blogging about DPM. Here is a compiled list of the DPM resources out there for you. These are online so they are updated on a regular basis.
The majority of DPM documentation out there is by Microsoft. The next best resource for documentation on DPM are blogs. You will see a list of DPM blogs later but here is a list of useful DPM documentation: