A Shortlist of Resources on the Psoas
This list will grow over time. This is just a start. :)
Daily Bandha comes through again with some cool looks at the psoas in a variety of poses. -see the graphic near the bottom of the page to see how the psoas reacts to various postures. Click here.
From the author of the Psoas Book. Click here for her own website and her ideas on treatment to release the psoas.