You can listen to radio reference feeds directly from safari without the need to download an app. I have been using scanner+ to stream my own scanner to my phone. Its the only one that I've found so far that will allow me to input a custom feed and will show the alpha tags without having to upgrade to the premium/pro version. However for some reason in the last day the tags have been out of sync, but i think that might partially be an issue with the computer serving the feed since its been having issues.
Matt / KC0VRV