Here are links to various web sites that I have found useful....

DRM radio sites -
www.drm.org (DRM consortium site)
www.drmrx.org (DRM forum site)
www.drm-info.de (comprehensive DRM site - German)
www.rnw.nl (Radio Nederland’s DRM page)
www.codingtechnologies.com (audio aacPlus™)
www.26mhz.us (US site)

DRM decoder software -
drm.sourceforge.net (Dream decoder software home page)
http://nt.eit.uni-kl.de/forschung/diorama/ (written in Matlab)

Digital radio sites including DRM and DAB -
www.digitalradiotech.co.uk (information on DRM, DAB, DTT, DSAT)
mysite.wanadoo-members.co.uk (info on all UK radio stations)