Freebbble!

From the author:

Tell me what do you think about it, feel free to use it for personal or commercial use, I just ask you to mention the credits and send me your wonderful works.

Freebie – PSD – About us & Metrics – Freebie is a free UI design resource made by Dribbble user Arthur Carayon. As far as I can tell, its license is Free for Commercial and Personal Purposes.

Helpful hint: Dribbble users are nice. If the license is unknown, it is usually because they forgot to mention it explicitly; not because they were being stingy. Ask nicely and they will probably allow you to use it.