Learning to become a doctor is no easy task.
Just to get in can be challenging enough, but once in the sacred halls of a learning institution, well, then the real learning may begin.
The following links are suited particularly for medical students.
MediWikis : fun new site I have found that shares information like wikipedia but medically orientated and validated by fellow students. Useful app for Android and Iphone too.
Almostadoctor : is a fairly comprehensive website with very good resources to help understand medicine. I particularly like its mind maps.
Geekymedics is a similarly useful revision focused website; I particularly find the body systems and OSCE stuff interesting. They are also on Facebook and twitter.
Money4medics deals with the less considered side of medical education namely help with funding it.
The studentBMJ provides a good resource and a great way for students to keep up to date with all that occurs in the medical world.