For those of you who are interested, Novell has developed a translator for OOXML for OpenOffice.org. It works on both Windows and Linux.
I installed it this morning on OpenSUSE without any hassle. I was going to install Alien on my Ubuntu machine and try the converter, but it turns out there’s already a .deb package for the translator. I did a bit of research on licensing because I had assumed that the Novell translator stemmed from their deal with Microsoft, but it looks like the translator(s) are actually due to the BSD-licensed OpenXML / ODF Translator Project. It appears the one by Novell only works on their special version of OpenOffice.org (Novell is doing a lot of new work on OO.o now that they’ve decided not to put up with Sun’s delays), but the Ubuntu one will work if you run a Debian-based distro, and it looks like ODF Converter will do the trick for everyone else.
Update:: Looks like it’s only for .docx; they don’t yet have support in for Excel, etc., only for Word documents.