Any device that has a browser which can generate HTTP(s) traffic utilizing a browser can use WLC Web Auth. If you're question is regarding being presented "automatically" with the captive portal I have seen this can be dependent on OS. From my reading about Droids (not hands on experience) the Android devices don't provide a captive portal query that would "automatically" bring up the WebAuth page when connected to an open network using L3 WebAuth security, but you then open your browser and try to hit any web page and you're fine. Apple IOS can handle this automatically (in most cases)
As long as the device can connect to the WLAN in question, open a browser, then try to navigate to some URL, it should work fine.
