There are a few on line sources out there -- they shouldn't be forgotten:
'Blue Histology' - IMHO the best site for learning histology:
http://www.lab.anhb.uwa.edu.au/mb140/
The site has awesome quizzes... MCQ and fill in the blanks. I probably owe half of my histology knowledge to that site.
One of my personal favourites is 'Virtual Autopsy' - this is fun even for medical students:
http://www.le.ac.uk/pa/teach/va/welcome.html
Pathology Outlines (
http://www.pathologyoutlines.com/ )
I think this is useful if you have a good foundation of knowledge. It is very widely used and probably the best recognized free source of pathology information out there. (It may be frustrating for someone starting-out... I came across it early in residency and remember being frustrated.)
Libre Pathology - (
http://librepathology.org )
Look & feel of Wikipedia -- but has a closed editorship. Very useful. Has interactive virtual cases at various levels of difficulty. Probably good for those fresh from med school. Site grew from a set of study notes for the pathology board exams. Disclosure: I've been involved with the site-- so, I may be biased.
University of Utah has a good site:
http://library.med.utah.edu/WebPath/webpath.html
Nice quizzes.
Wikipedia -- said to be fairly good for pathology:
http://www.ncbi.nlm.nih.gov/pubmed/20653388
On the paper front:
Molavi's - probably the best book for those starting out. (Unfortunately, I didn't discover it until well through residency.)
The Washington Manual is a good general summary, information dense and not too expensive.
Robbins & Lester are pretty much required reading... but I can't say I'm a huge fan of either.
Cheers!