[Resurfacing this helpful post from Jeff Tranberry's Digital Imaging Crawlspace, which Adobe has apparently taken offline...]
UsTwo has released an update to their wonderful resource for "Pixel Perfect Precision."
Download: Pixel Perfect Precision (PDF 24MB) | Pixel Perfect Precision (iBook 28MB)
This amazingly useful handbook covers the dos and don’ts of design for user interface designers, covering topics ranging from general design principles including navigation, interaction, error handling, accessibility; to Photoshop specific topics including color management, layer organization, pixel precision using vectors, Adobe Generator for asset creation, and much more.
Follow the creators @PPPUsTwo and @gyppsy on Twitter.