Scott, I see now. Common topic. Corporate users with personal devices connecting to Corporate network.
On the controller, if you go into the Statistics section and then expand the tree - highlight an RFDomain in the tree that you want to look at. In the middle vertical column, select 'Wireless Clients'. The information on the right will then give you many columns of details about each of the wireless clients that are using the wireless at that Site you've selected...including the WLAN they're currently associated to.
Now...if you're wanting to look at this sort of information from a historical perspective, that capability exist on the NSight platform (historical/trending/troubleshooting/reporting tools)