Additional Books
Donald Knuth's Art of Computer Programming is the book on algorithmic aspects of programming. It currently consists of three volumes, covering Fundamental Algorithms, Seminumerical Algorithms and Sorting and Searching. Four more parts are planned.
Lecture Notes and Articles
Background and History
Bernard Chazelle's The Algorithm: Idiom of Modern Science
The Clay Institute's P vs NP Millenium Prize
Advice on Problem Solving (postscript, pdf)
Recommendation systems, or, how to make money out of algorithmics