Coucou Icons is a free set of scalable vector icons created by Anny Chen and Julien Rousseau. Coucou was an idea to create a fun but well crafted icon set,and then make it free for anyone to use.

You can use these icons under Licensed under the Creative Commons 3.0. 100% royalty free, but you canot use these for commercial purposes. Attribution - You must give credit to Coucou Icons (www.coucouicons.com) wherever you use the set.

I am awaiting further clarification of the license, i.e. can i use them on a business site.