The Open Office suite that installs with Kubuntu can read Office 2007 formats (e.g., .docx for Word, .pptx for PowerPoint, etc.). But the filter is pretty rudimentary — it pretty much just draws in plain text.

http://katana.oooninja.com/w/odf-converter-integrator has packages that include a much better filter along with the integration hooks required for Open Office. The resulting document has special characters, graphics, headers, footers — the works.

The only hitch I found is that I already had the odf-converter package installed which prevented the integrator from installing. I guess it has its own copy. The key was to use apt to remove the existing converter and then install the integrator as described on its Web page.