Indeed. People seem to be making an awful lot of assumptions about how this service is supposed to work and getting very excited, but we're very light on details. People keep going crazy about transferring content from the iPad to an Apple TV, but if you do can you use any other applications? Has Apple discussed the rights issues with any content providers? Does it require coding into apps specially? Can it even work in a web stream through mobile Safari (I'd wager no)? Does this mean that all that traffic goes through my internal wi-fi network twice?
Phazer
NO assumptions to make, audio has been streamed this way using airport express for years, it's simple plug and play - plug your speakers into airport express and they list in a pull down in iTunes for audio playback. The new tech is just an extension of this, and devices are being launched with the transceiver already inside.
The rest of your questions seem negative in their tone, but yes I'd imagine apple has been speaking to third party companies, otherwise these new devices wouldn't exist.