Here are some websites that you might find helpful.
This is a great site with loads of information on basic music theory. Click on the 3 buttons on the left that say pitch, chords, and time.
This is a website full of information about jazz history and jazz education.
If you want to get serious about learning everything about the circle of fifths, this website is for you!
This is one of the biggest jazz websites on the internet. It has loads of information regarding album reviews as well as a wonderful forum to ask all your jazz questions (but don't be afraid to ask me first on my contact page!)
This is a jazz community website
This is a very handy website that has really improved my ear over the years
This is a great site to listen to music for free! Basically you enter an artist you like and Pandora will create a customized station with similar artists for you to discover.