Free UI Kits at Dribbble-- useful to get something looking polished when you don't have a graphic designer at the ready.
Square UI Kit is an absolutely new PSD User Interface Pack including a set of beautiful and pure components, which you can use in creating the design of any project.
This is one element of a UI kit I'm working on. I'm going for simple and clean design. Hoping to give up part of the kit as free PSD.