The Inquirer has a piece detailing SCO’s plan to “challenge the validity”:http://www.theinquirer.net/?article=11031 of the GPL. Their argument hinges around a federal law which states that only a single copy of software may be made for backup purposes. By this reasoning the GPL’s is void, as it states that you can make as many copies of the software as you wish, as long as all copies (and derivative works) are also released under the GPL. Apart from the fact that the inquirer seem to confuse the whole issue of copyright (contrary to the article, just because you release software under the GPL it doesn’t mean that you don’t have copyright of the work, just that you’ve chosen to allow its use under the GPL), they also miss the point that SCO’s legal challenge to the GPL applies equally to other open source licenses, such as the Apache and BSD-style licenses.
I am sure that the original Federal law was drafted with commercial software in mind (the US government runs its fair share of Open source software), but it looks like we’re going to have to wait until next year at the earliest when the SCO-IBM case finally comes to court to see this point clarified.
_Updated (11:23am GMT)_: I sent some comments to the Inquirer and they seem to of updated their article a little, although the misleading comment concerning copyright seems to remain.