Biography.com: Brouwer, Luitzen Egbertus Jan: Biographical paragraph.
Brouwer: A drawing of the Dutch philosopher by Soshichi Uchii, with a note on Brouwer's teachings.
Brouwer's Cambridge Lectures on Intuitionism: Text of the first lecture, as published in 1951, and selected fragments of lecture notes by Brouwer.
Luitzen Egbertus Jan Brouwer: Article from the Stanford Encyclopedia of Philosophy, by Mark van Atten. Includes biographical timeline and a summary of Brouwer's intuitionism.
MacTutor History of Mathematics: Brouwer: Biographical article by J.J. O'Connor and E.F. Robertson, with links to related topics.