This page outlines the best links to reference sites, articles and PMO relevant organisation. For some of the article sites make sure you add the term 'PMO' into the site specific search field to get more targeted project office information:

REFERENCE
www.projectreference.com/
www.allpm.com/
en.wikipedia.org/wiki/Project_management
www.e-programme.com/
www.gantthead.com/
www.pmforum.org/
www.allpmo.com/
www.hyperthot.com/pm_meth.htm
www.pmportal.co.uk/
www.pmtoolbox.com/
www.projectsmart.co.uk/
www.pmhut.com/ 
www.projectperfect.com.au/
www.protoolkits.com/

ARTICLES
http://www.computerweekly.com
www.cio.com/
www.computerworld.com/
www.developer.com
www.itworld.com/
www.gartner.com
http://www.pmtoday.co.uk/
www.maxwideman.com/

ORGANISATIONS
http://www.apm.org.uk/
communities.pmi.org/home.jsp
www.apmg-icp.com/
www.pmosig.org
http://www.imc.co.uk/
http://www.mca.org.uk/