Tono,

Podcasts are normally .mp3 files or some other compressed audio format. This is what makes it irrelevant for mobile phones. Any of the smart-phones on the market (dominated by Android based phones, but also iPhones) can play .mp3 files and handle podcast delivered audio.

That's the point I was trying to make about mobile phones.

Unless you have a way to print the QR codes for people to scan them, they aren't of much use. Do you plan to somehow advertise in print media for your podcast? If so, then the QR code makes sense. If not, then there's really no point in generating and using QR codes.