Hopefully, you've already seen Airfoil for Mac 3, our recent major upgrade to Airfoil. If not, you can have a read through the Airfoil 3 tour to see what's new in our AirPort Express extender.

One of the biggest new features in Airfoil 3 is Airfoil Speakers. With Airfoil Speakers, you can turn any Mac (running Mac OS X 10.4 or up) into a virtual AirPort Express. With Airfoil Speakers and Airfoil, you can send audio from one Mac to other Macs, as well as to AirPort Express units.

We've already had a lot of great feedback on it, with users expressing an interest in both Windows and Linux versions, to run on spare machines around the house. We'll see what happens as far as a Linux version goes, but we're nearly done with Airfoil Speakers for Windows. Now, we need you to help us test it out.

If you're interested in testing out the Airfoil Speakers for Windows beta, great! All you need is a Windows machine, and a copy of Airfoil for Windows or Airfoil for Mac. Of course, Airfoil for Mac and Airfoil for Windows can each send to Airfoil Speakers running on Mac or Windows. To test, sign up at through our tester forums. Once you have an set up account there, send an email to us with your full name and username, and we'll add it to the Tester group.