Articles on Jazz Improvisation- Some articles about jazz improvisation and harmony by professor Joan Wildman of the University of Wisconsin.
Basic Jazz Improvisation Primer- A basic primer on jazz improvisation by Michael Furstner. Deals with using chord root tones and chord guide tones.
Brent D. Stuntzner's Jazz Guitar Site- A jazz guitar site featuring several free transcriptions of solos by some of jazz guitar greats. Formats include standard notation, TAB, MIDI, and Jam Tracks.
Jazz Arranging Tutorial- Doug Bristol's site is a good reference for those interested in learning the basics of jazz ensemble arranging.
Jazz Guitar Improvisation in One Lesson- Jazz guitar online diagrams outline limits of classical jazz harmony in major with improvisation options. More than isolated chords or single key area map. No previous theory required.
Jazz Resource Center- JRC offers many music theories for jazz musicians and students. The site includes a systematic approach to piano voicings and scales as well as transcriptions.
Just Jazz- An extensive discussion group dealing with jazz theory, harmonization, arranging, and other topics related to playing jazz.
Learn Jazz Piano by Scot Ranney- Free online jazz piano lessons with graphical and audio examples of different styles and approaches. Also includes jazz piano discussion forums.
SoYouWanna Learn About Jazz?- Full length article discusses the fundamentals of jazz appreciation, including history, styles, and personalities.