You can create a CC-portal on your site for browsing CC-licensed content. This could be based upon tag, internal marking of licensing, or any way you see fit to limit browsing. Good examples are provided by Flickr (http://flickr.com/creativecommons) and Jamendo (http://jamendo.com/creativecommons/).
Some sites facilitate search based on license properties, typically (1) any Creative Commons license, (2) Creative Commons licenses that allow remix, and (3) Creative Commons licenses that allow commercial use. See CC search integration for several examples. Other instances of search engines with these capabilities built-in can be found at the Creative Commons search page.