Some interesting sites/readings worth visiting as follows:
http://www.pmi.org (PMI website)
http://www.pmzilla.com (PMZilla)
http://pmzilla.com/comprehensive-pmp-notes (PM Zilla - Summary Notes)
http://pmzilla.com/memorizing-inputs-tools-and-outputs-pmp (PM Zilla - Memorizing Inputs, Tools and Techniques, Outputs – ITTO’s)
http://www.oliverlehmann.com (Oliver F. Lehmann)
http://www.oliverlehmann.com/pmp-self-test/75-free-questions.htm#providers_ (OFL - free PMP Exam Self-Assessment Test and link to tons of Providers of Free PMP + CAPM Preparation Questions)
http://www.velociteach.com (Andy Crowe)
http://www.rmcproject.com (Rita Mulcahy – RMC Project Management)
http://www.cornelius-fichtner.com (Cornelius Fichtner)
http://www.project-management-prepcast.com (Cornelius Fichtner)
http://www.project-management-flash-cards.com (PM PrepCast free flash cards)
http://www.kimheldman.com (Kim Heldman)
http://www.simplilearn.com (Simplilearn)
http://www.pmstudy.com (many saying sample exams close to real one)
http://www.deepfriedbrainproject.com (cool site – PMP Exam Prep Blog)
http://www.brainbok.com (cool site – various topics)
http://quizlet.com/subject/pmp/#http://quizlet.com/subject/pmp (cool site - various subjects)