Wireless transmission of sound

I'm kind of stuck with this little project. For it, I need to wirelessly transfer sounds from the arduino input, through the computer to my speaker. Let me explain a bit more schematic.

analog sensor -> arduino -> computer (process info into sound) -> speaker 20m away from computer and arduino.

How do I go about this? I already have some experience with XBee's, but it seems inefficient to convert an analog signal to digital, then transfer it, and then convert back to analog. Is there a way to do this in an analog way? Like FM transmitters and receivers? And then with receivers as small as an xbee?

Found this at sparkfun, but I'm not sure whether that is what I need. I would really like to just plug the transmitter in my 3,5 jack of my computer and then connect a small speaker to a small receiver (preferably 3,3v). Can somebody confirm whether this will work? http://www.sparkfun.com/commerce/product_info.php?products_id=8770 If not, what will? Thanks for the help in advance

Sparkfun sell FM transmitters and receivers but its probably simpler and cheaper to use a wireless MP3 adapter (an FM transmitter with a 3.5mm jack) and a standard FM radio receiver.

Something like this: http://www.audio-mania.co.uk/shop/p119/FM-receiver/iTrip-for-Ipod/MP3-Players/product_info.html?gad=CO_-wfwCEgjyoGKYlN-x9Bidktf5AyCH56Md

Yeah I know those, but don't those only have a really short range, since they are only used in the car? I need something like 20 meters.

And that doesn't solve the receiving part, which really needs to be small....

The transmitters claim a 20 or 30 meter range. You can probably achieve that if you have line of sight of the receiver and not much interference. I don't know what they use for an antenna but some research on google may yield some tips on extracting the maximum legal output.

Have you done any searching for a small fm receiver? Or you could always use something intended for headphones with a small audio amp and speaker.