Originally Posted by: BlochThe new Ultimate Scale Finder is a great tool and fast to use.[/quote]
I agree! The GT programming team did a great job on it! :)
[QUOTE=Bloch]I kindly aks you to give some lessons about when and how to use the individual scales. E.g.: When do I use the mixolydian scale?

There are two basic categories of why to use any given scale or mode:

1. Functional use, which means to pick a scale that functions with (is part & integrated) the chords you are playing over.

These tutorials will show you the functional approach; how, why & when to improvize in general (how to pick a scale to use for soloing over a chord progression):

http://www.guitartricks.com/tutorial.php?input=876
http://www.guitartricks.com/tutorial.php?input=483
http://www.guitartricks.com/tutorial.php?input=491

2. Ornamental use, which means you pick a scale or mode to use simply because you like the sound of it regardless of how it functions with the chords in the music.

These will show you the ornamental approach; two tutorials on modes, how, why & when to use them:

http://www.guitartricks.com/tutorial.php?input=370
http://www.guitartricks.com/tutorial.php?input=770


Hope this helps! Let us know how it goes for you. Have fun!