Can't help much with the internet radio problem... as I was having the same issue.

I tried to add BBC Radio1 using the same URL used in Media player (for the real player stream) but it wouldn't use it.

However - for podcasts, look for the rss feed url for the podcast that you want to add..

For example, if you're wanting to add BBC podcasts, check out:
http://www.bbc.co.uk/radio/podcasts/directory/

sometimes, once you've entered the url and hit "return" you need to select it and hit "return" on the softkeyboard again to get it to register.

Hope that's some help