One of the best sources of scientific info is of course the Web.
Use just about any search engine (e.g. Alta Vista at http://www.alta-vista.com)
 and search for the keyword "radiology". There's plenty there - in fact you may well want to
enter other keywords to narrow the search criteria to more specific areas you're interested
 in.

Here are a few specific links that might provide a starting point:
http://www.radiology.com
http://hammate.cbcu.cam.ac.uk/clinschool/radiolog.htm
http://www.mds.qmw.ac.uk/radiol/links.htm
http://www.acr.org/
http://www.rsna.org/
or of course (since we were involved with its site!)
http://www.rcr.ac.uk/enquiries/college/page0001.html

As an alternative (or in addition) to the Web, at least here in Britain, is the reputable
 journal "Clinical Radiology", published by WBSaunders (http://www.hbuk.co.uk/wbs/). In
 America there is the journal "Radiology", published by the Radiological Society of North
 America (http://www.rsna.org/REG/publications/rad/rad.html).