There's a wealth of pages with information and thoughts about Glenn Gould and his works. Here are just a few:

F_minor -- a Glenn Gould mailing list, so named due to Gould's remark that if he were a key, he would be f minor because "it's rather dour, halfway between complex and stable, between upright and lascivious, between gray and highly tinted...There is a certain obliqueness." 

Sony's biography of Gould.

Some lovely photographs of Gould. This is my favorite among them.

An interesting article in Music Theory online about tempi in the 1955 vs 1981 Goldbergs, and listeners reactions thereto. Highly recommended. 

...more links to come...