Mac+,
If you want to do write-ups on the different modes, I'll gladly throw them in. I could change the mode radio buttons into a drop-down like you suggested, giving me the space to pop in a textfield with descriptions for each mode.
I was planning on adding a drawer to the bottom of the window that would pop out with chord information. In the drawer would be either radio buttons or another drop-down so the type of chord (triad, 7th, extended) could be selected, and the appropriate chords for the scale (for example, IMaj7, ii-7, iii-7, IVMaj7, V7, vi-7, vii-7b5 for Ionian) would then display in the drawer.
I don't know what kind of explanations to include for the chords but if you have anything to offer, again I'll gladly include them.
At least, that's the plan.
Of course, I'll credit you in the updated About screen for anything you contribute. Since this program is free (and will stay that way) I can't offer you any $$ but if you have a webpage, your credit on the About screen would be a link to your site.