Apple’s iAd mobile advertising network was originally launched as a way for big brands to advertise within iOS apps – and as a new revenue stream for iOS developers. It’s not been a roaring success, but now Apple may be about to refocus iAd as part of its upcoming ‘iRadio’ streaming music service. At least, that’s what Bloomberg is reporting. “Engineers and sales staff in Apple (AAPL)’s iAd business have been charged with supporting the new digital-radio service,” it claims. “Apple will seek to land big brands for the new streaming-radio service – akin to Pandora Media Inc’s business model – scaling back its role as a network that places marketing messages in mobile software from its App Store.” The article reiterates previous speculation that iRadio (or whatever it’s called) will be free, ad-supported and “tightly integrated with iTunes”. That means more labels will be expected to start using iAd: the theory being that iRadio will be the perfect place to market digital albums – certainly a better place than Pandora. Much will depend on pricing, though: one of the reasons iAd didn’t really take off before was the multimillion per-campaign spend Apple asked for from brands, although that’s come down over time.