Sound on Sound – A go to for audio mixing, hardware/software do’s and dont’s
Todaysbeats – Great site for learning chord progressions and other fundamentals
Home studio corner – Awesome tutorials, discussions, tips & tricks for musicians/engineers
Future Producers – Good professional insight forum
Secrets of the Pros – A great look at the tricks of the trade from “inside” the industry
Gear Slutz – A no brainer for most engineers/musicians but if you haven’t ended up here, check it out
Studio Buddy – This is a decent tool that can help with studio/recording issues
AudioTuts – Nice professional tutorial videos for musicians