Via a Groklaw News Pick,
Stuff.co.nz is reporting that:

In a stroke of irony, Microsoft’s Halo movie will be produced in Wellington by servers running the open-source Linux operating system.

Weta Digital uses more than 1000 dual-processor IBM blade servers running the Fedora version of the Red Hat distribution of the Linux to produce special effects for movies that have so far included Lord of the Rings and King Kong.

Microsoft will receive $US$5 million up front from Universal Pictures and Twentieth Century Fox, plus a cut of ticket sales.

I do so hope that their will be a credit for Linux at the end!