[Dovecot] Global Sieve File

Is anyone here using a global Sieve file that handles messages for an entire server with many users? I understand and use local Sieve files, but I would like to learn more about how to set up Sieve to filter ALL incoming messages using a single file. I would love to read about how you managed to get it working.

I'm running Fedora 10 with Postfix 2.5.5 and Dovecot 1.2.rc2.

Thanks for any insight!

James