It's like a really shit movie plot—a developer has cracked Apple's code for Airport Express and published an emulator online for all to see (and grab), which emulates the wireless networker. That means you can use Airplay to stream music to other computers, games consoles...
I don't know, you wait months for AirPlay products, and then two come along at once! Just like buses. JBL's On Air Wireless speaker (left) actually includes a little screen for displaying track info, though obviously if you're streaming over AirPlay you could just look at the iPhone screen instead.
Want to use AirPlay, but don't have an Apple TV? There's hope for you yet. TUAW's Erica Sadun put together an app which'll allow your Mac to stream media from an iPhone by pretending to be an Apple TV.