Annotated Webliography

http://www.corpusthomisticum.org/ Full edition of the complete works of Aquinas, plus bibliography covering all the studies on Aquinas and his doctrine.
http://www.newadvent.org/cathen/14663b.htm entry on Aquinas in the New Advent Catholic Encyclopedia.
http://www2.nd.edu/Departments/Maritain/etext/thomism.htm Article on Thomism by the Jacques Maritain Center of Notre Dame University.
http://gutenberg.net.au/ebooks01/0100331.txt biography of Aquinas by G.K. Chesterton, at Project Gutenberg
http://plato.stanford.edu/entries/aquinas/ Entry on Aquinas in Stanford University Online Encyclopedia of Philosophy. Useful for students.