Here is a collection of sites based on music theory and fundamentals, I encourage anyone looking to perfect there music skills at least skim through this material and try to obtain a grasp of it.

Basic Music Theory- Great site of info as well as tests for Music Theory.

Music Theory Site 2- Going over the basics.

Basic Music Fundamentals- Great site with Tests on each area of the standard fundamentals.

Chord House- Great breakdown of how a Scale is made by half steps.

Note Trainer- Teaches you to memorize the locatation of a note on a staff.