By subject

Surgery http://www.surgical-tutor.org.uk
Anatomy http://www.bartleby.com/107 http://www.instantanatomy.net
Physiology http://www.mednotes.net/notes/physiology
Embryology http://embryodynamics.com/?page_id=553
Biochemistry http://themedicalbiochemistrypage.org
Microbiology http://www.bmb.leeds.ac.uk/mbiology/ug/ugteach/dental/tutorials/list.html
Pathology http://pathlab.org
Genetics http://www.uic.edu/classes/bms/bms655
Pharmacology http://www.pharmacology2000.com
Immunology http://www.mednotes.net/notes/immunology
Histology http://histology.med.umich.edu/schedule/medical https://mospace.umsystem.edu/xmlui/bitstream/handle/10355/11238/KrausesEssentialHuman.pdf?sequence=1

By systems

Cardiovascular http://www.cvphysiology.com
Gastrointestinal http://www.medquarterly.co.uk/mq88/index.php?option=com_joodb&view=catalog&Itemid=70&lang=en
Endocrine http://www.oscehome.com/Endocrine-OSCEs.html
Musculoskeletal http://www.scribd.com/doc/15789119/Musculoskeletal-System-lecture-notes-ppt
Neurological http://medicalppt.blogspot.com/2011/02/neurology-lecture-notes.html
Respiratory http://almostadoctor.co.uk/content/osces/examinations/respiratory-exam
Renal http://almostadoctor.co.uk/content/systems/nephrology/renal-failure

Specialities

Anaesthetics http://www.medrevise.co.uk/wiki/Anaesthetics
Obstetrics and Gynaecology http://www.medrevise.co.uk/wiki/Obstetrics_and_Gynaecology
ENT http://www.uwoent.ca/files/Clerkship_Lecture.pdf
Emergency Medicine http://maggiegordon.com/medicine/TorontoNotes/Emergency%20Medicine%20PDA.pdf
Psychiatry http://www.trickcyclists.co.uk
Dermatology http://dermind.tripod.com
Radiology http://www.learningradiology.com/medstudents/medstudtoc.htm
Oncology http://medilectures.blogspot.com/2010/03/oncology-lecture-notes-pdf.html
Haematology http://usmlemd.wordpress.com/2009/01/15/727
Geriatrics http://www.angelfire.com/md2/liaquatian/Geriatrics.pdf
Infectious Diseases http://www.medicine.mcgill.ca/tropmed/txt/lecture1%20intest%20protozoa.htm
Internal Medicine http://medschool.swmed.edu/intmed/notes.htm
Paediatrics http://medicalppt.blogspot.com/2011/02/paediatric-lecture-notes.html

Clinical Examinations and Procedures

Evidence-Based Medicine

Free Online Medical Books

NCBI Bookshelf http://www.ncbi.nlm.nih.gov/books
Free Books 4 Doctors http://www.freebooks4doctors.com

Miscellaneous

Revise 4 Finals http://www.revise4finals.co.uk/cms
Medical Finals http://new.medicalfinals.co.uk
Fastbleep http://www.fastbleep.com
Money 4 Med Students http://www.money4medstudents.org/index.asp?id=1
NHS Discounts http://www.nhsdiscounts.com/vouchers-discounts-shop-offers-for-nhs-staff.asp?from=nav
Medical Dictionary http://www.mondofacto.com/dictionary/
UK Clinical Ethics Network http://www.ethics-network.org.uk
Nuffield Council on Bioethics http://www.nuffieldbioethics.org
Medical Ethics (BMA) http://www.bma.org.uk/ethics/index.jsp
Clinical Trials http://clinicaltrials.gov
Cochrane Library http://www.thecochranelibrary.com/view/0/index.html
NHS Direct http://www.nhsdirect.nhs.uk
NHS Evidence http://www.evidence.nhs.uk/default.aspx
Medline Plus http://www.nlm.nih.gov/medlineplus
Med Bio World http://www.medbioworld.com
The Merck Manuals http://www.merck.com/mmhe/index.html
Healthcare Professionals Crossing Borders http://www.hpcb.eu
Parliamentary and Health Service Ombudsman http://www.ombudsman.org.uk
The Patients Association http://www.patients-association.org.uk