Behance is described on http://www.behance.net/about as “The leading online platform to showcase & discover creative work. The creative world updates their work in one place to broadcast it widely and efficiently. Companies explore the work and access talent on a global scale.“.
Of course, you’ll find amazing work in graphic design, architecture, photography, illustration, etc., but what you may not know is that Behance is a great place to find really good UI/UX designers too.
Check out some of the portfolios in the UI/UX category — http://www.behance.net/search?field=132 —
The community of Behance users is huge and growing. Check out these stats — http://www.behance.net/facts