There is a media frenzy on this - it's not just me. Zidane's family have been interviewed on the phone and reckon he was possibly called a Harki or terrorist. The Mirror has a piece on all the various conspiracy theories. Interesting piece worth reading on lipreading in the media.
The Associated Press reports that the Parisan anti-racism organization SOS-Racism stated today that "several very well informed sources from the world of football" say Materazzi called Zidane a "dirty terrorist."