Hi,
Those modules recommended don't have the bandwidth to cope with audio, perhaps compressed telephone quality audio but certianly no where near enough for Hi-fi. Also, they are digital, so you would be forced into encoding analogue audio to digital, then decoding it...real hassle.
Ultimately you must decide range, and quality. And also power! Even wireless speakers need power, batteries will only last so long and have limited power. I would suggest looking for an analogue FM circuit, running at a license free band. I believe the standard FM 88Mhz-108Mhz has been released for ultra low range systems. (like those FM transmitters for iPods). Not the best quality in the world, and you could get interference, but its probably the 'simplest' way for DIY.
The second approach I have experience in, is digital. Its expensive, complicated, but it can allow you to get CD-quality audio over a decent range, without dropouts. Considering it is for qireless speakers, latency will not be an issue (if they are the only speakers producing sound) so you could consider compression techniques so that it uses a lower bandwidth...and so allows you to use 'off the shelf' wireless modules, Would still require a good 500kb/s - 1Mb/s though.
As I said, a simple analogue system would probably suffice for your needs. Google 'Fm transmitter circuit' and I'm sure you'll find plenty of schematics. Two different transmitters, for each channel, tuned to different frequencies, and then in each speaker you could have a cheap FM radio, with a power amp. Beware of intreference.
Blueteeth