Electronic Music Resources
Audio Engineering I
Audio Engineering II
A massive, searchable database of microphone specs. Very comprehensive and informative!
Another microphone database on the recordinghacks website. Also very comprehensive. Many models include download links to reviews, articles, the manufacturer's spec sheets, and manuals.
Companion website to the book Mixing Secrets for the Small Studio, by Mike Senior. Lots of great info and advice, but most useful is the massive library of free, high-quality multi-track song downloads that you can use to practice mixing!
Great tutorials and articles from Universal Audio on mixing, recording, and editing studio techniques.