I'm guessing everyone knows Hifi Engine and Hifi Manuals and Manuals Center and the like. I recently had to go elsewhere and found http://www.stereomanuals.com/. This isn't a free site and has a mix of scanned and printed archived manuals. You will need to wait for the postman if your required manual is only available in hardcopy, as they don't scan on demand. Anyway, I'm putting this up as an additional resource because they provided great service and rely largely on word of mouth.
