While this might count as a shameless plug for my own material, this is also a service for learning guitarists. http://www.alluvialgems.com/BookIndex.htm this has a list of the 174 tunings in my book. The useful part is I have posted audio files in .wav format for every one of them. There are also links to sites of artists that use these tunings. The displacement code is based on standard tuning by half steps. This will show how to get to any tuning from standard, so there is no ambiguity of what the tuning sounds like or how to get there. While my book might help, this information will give a beginning or intermediate guitarist more than enough to chew on w/o shelling out $$$.