P&S oil is marketed for psoriasis. I got it off www.dermadoctor.com
Here is the link to the product so you can read about it: http://www.dermadoctor.com/product.asp?WID=%7B05A04EEC%2DC023%2D473B%2DB5D7%2D7C1D6FF4A0FD%7D&productid=206
I put it on A's hair overnight, which I think was a mistake for someone so young. I didn't have a problem with it getting anywhere -- I rubbed it into her scalp while she was in the tub, and then combed it through when we got out. Next time I think I'll bathe her in the morning with it, and wash it out at lunch. She had it on for 12 hours (that's how long she sleeps), which was way too long. I think maybe 5 hours would be good. Her poor little scalp is STILL red, but she insists it feels fine. I think she's so used to being uncomfortable she doesn't notice. Poor little baby.
I didn't order the shampoo, because the shampoo is just 2% salicylic acid, and I can use T-sal for that. It also has the dreaded methylparaben in it (and animal protein?). I know Erin uses P&S, though, so maybe she's tried the shampoo.