Hi,
thanks for asking this question!
The preloaded radios are mostly from Soma FM (
somafm.com), because they provide direct link to the streaming URLs. We support also .m3u files (because they are just plain text files with the direct streaming URL), but we have found that they sometimes do not work as they are handed over to the Android media player and it sometimes can't read them. We have a fix for that in the beta that will be released probably tonight.
You can also open the .m3u file in a text editor and type in the URL on Your own.
If there is no .m3u neither a direct URL, there are actually websites that gather and list these files/URLs. Take a look at
http://www.listenlive.eu/ for an example.
Thank you very much.
Best regards,
Jiri Richter
Urbandroid Team