As far as I know there isn't anyone: everyone ive talked to on the subject has learnt by looking at twm and aewm++. I have found some info on typical WM functions but no tutorial. Ive started hacking on aewm++ and im starting to understand stuff but it would be ALOT easier with a tutorial.

I started on a wm ages ago, and when I did there was no specific WM programming resource on the net. I used #xlib on freenode, simple wms (I think there's a simpler one than aewm, not sure) and generaly xlib resources.

Good luck, you'll need it.