Apple won’t let you stream the AirPlay way from your Mac or PC to any other iOS device. Only the opposite and only if you have an Apple TV or an AirPlay-enabled device. However, Apple permits apps to stream the AirPlay way for you.
And here comes a fine new (well, not so new) Mac and iOS app called AirFoil.
Simply to put, AirFoil is awesome. Awesome like, (awesome)^e. AirFoil sends audio to remote speakers including iOS devices, other computers, and hardware devices like the Apple TV and AirPort Express. Plus, it supports multiple audio—that is, you can send audio to multiple outputs around your house and not just Apple’s approved hardware, all in sync. Not only that, but AirFoil supports also DVD & video playback, web-based Last.fm & Pandora plus Spotify streaming, complete metadatas from your library and many more cool features.
Literarily, there’s no setup. Just download the Mac and the (free) iPhone/iPod/iPad app (it’s called AirFoil Speakers Touch, find it in AppStore) and you’re good to go. Yes, that’s the only thing you have to do. Here’s how it looks.