“a modern prototyping tool. It can help you to quickly build and test complex interactions and rich animations for both desktop and mobile.”
mobile_design
UX Archive
Lays “out the most interesting user flows so you can compare them, build your point of view and be inspired.” Handy.
iPhone 5 PSDs
A nice collection including PSDs that can be printed for sketching as well as vector versions for high fidelity design.
iOS Photoshop Actions & Workflows
A must have for all iOS designers.
About those vector icons
The most comprehensive explanation as to why we still use raster icons instead of vector, and why SVG is not the answer.
Android niceties
“A collection of screenshots encompassing some of the best (IMO!) looking Android apps, and / or apps with interesting user interfaces, hopefully providing some inspiration and insight into Android UI conventions.”