A nice web site for 13C chemical shifts. There is also a 1H page that lists lots of examples, not particularly useful for trend analysis but great for looking up a particular shift.
Demonstrations of chemical reactions and how to do them. Descriptions of the procedures and the underlying principles are well presented, though sometimes only in German.
Linus Pauling A collection of Pauling's papers, photos, letters, etc from the library of his alma mater, Oregon State University.