Lots of good stuff in here on Photoshop / illustrator as well as a rake of good design / accessibility advice.
http://cdn.ustwo.co.uk/PPP/PPP2.pdf
from: http://www.ustwo.co.uk/blog/the-ustwo-pixel-perfect-precision-handbook-2/
http://cdn.ustwo.co.uk/PPP/PPP2.pdf
from: http://www.ustwo.co.uk/blog/the-ustwo-pixel-perfect-precision-handbook-2/