Troy wrote an answer about Scarpa Booster Climbing Shoe - Discontinued Vibram XS Grip on July 27, 2011
I wear 42 street shoes and my boosters are a 381/2. The break in period is painful but once you get them worked in a bit they're an amazing shoe. The heel is meant to stretch a TON so even if they seem small (I would recommend 39's for yourself) they will eventually break in (probably 2 weeks of solid climbing). They should feel like ballet shoes when you put them on and you should want to rip them off after every run on the wall.