The free PDF download of "Sound the Trumpet: How to Blow Your Own Horn" (320pp) will be offline soon. The Hal Leonard Corp. has bought the rights to "Sound the Trumpet" and it will be out November 1 under the title "All About Trumpet". At that time the free PDF will be taken offline. It's a great book. If you're interested, go download it before November 1!
There is also a free theory book at the site, too. Go to:
Sol-Ut Press: Fun Music Learning and follow the links.