Apple has reacted swiftly to a piece of software which allowed users to purchase software from the iTunes software without the DRM that usually comes with such a purchase.
PyMusique, created in part by the infamous Jon Johansen (readers may remember him as DVD Jon, the man behind the DeCSS program), worked by exploiting a loophole in the iTunes store, and provided an alternative front end to iTunes. Users were able to preview songs, signup for accounts, buy songs, and redownload songs that were previously purchased with PyMusique.
It is not really a surprise that Apple have closed off this loophole, as part of their success can be attributed to the fact that once bought, songs cannot easily be copied. What will be interesting to see is if legal action is taken by Apple against the creators of PyMusique, who are convinced that they have done nothing wrong. If it turns out that they are wrong, we'll let you know. No doubt Apple has some lawyers on the case as we write.