[http://klumpp.net/blog/archives/83-Tabellen-aus-OpenOffice-nach-LyX-TeX-LaTeX-exportieren.html This is a translation of the article's German version.]
Lyx (http://www.lyx.org/) is a swell thing to use. The power of TeX paired with an approachable GUI. But just that interface fails when it's about tables - not so much when it comes to //editing// tables, but rather //importing// them: From spreadsheet programs like OpenOffice Calc.
But especially scientific work wants you to //actually// compute and calculate stuff, and manually bringing the results piece by piece into a LyX table can really be bothersome.
A pragmatic help could be Shohei Abe's "Calc2LaTex" macro (http://calc2latex.sourceforge.net). Officially, it's only tested up to OpenOffice 2.0, but it also works quite well under version 2.4.
EDIT 2012-11-19: So, in the mean time, someone did a good deed and built an extension upon Calc2LaTeX, suitable for Apache OpenOffice 3.0+. Have a look: http://extensions.openoffice.org/en/project/Calc2LaTeX. Can anynone confirm this working with LibreOffice?
http://klumpp.net/blog/ am : Tabellen aus OpenOffice nach LyX / TeX / LaTeX exportieren