Now you can download Free well-known popular web UIs reproduced exactly in Photoshop for educational purposes. Popular UIs is a website which creates and freely shares PSDs of well-known websites.

The files are provided for educational use, to help people learn from them, and the PSDs include the layouts of GitHub, Facebook, Apple  and more.

It is mentioned that more will be added regularly. Also, the project is open source and anyone can contribute.

Popular UIs — Freely Shares PSDs Of Popular Websites