Just wondering if anyone out there knows if this would work with iPhone 5s?
I'd like to stream online radio through it…

Thanks..

Depends what you consider online radio. There are many smartphone apps that stream worldwide radio stations.

I use the tune-in radio app on both iOS(apple) and Android for the BBC channels and talksport.

If you are referring to something like shoutcast then I cant offer an advice as I have never used it.

Yes.. I mean tune in radio..

Both free with ads and paid for versions of tunein are available for iphones (and android)

Paid version of tune in is well worth it as it 'pauses' the radio when a call comes in. You can ofc just press pause as well, and you can record whole shows and schedule recordings.
If you listen to the radio a lot then the few quid is good value.