How do I change the default file permissions for files created on a Mac server? In case it's relevant, this is a Mac Mini running Mac OS 10.6.7. It's currently used mainly as a file server, and there are several users who need to share files. These files need to be writable by all, rather than the default which is writable only by the owner.

I've been trying to do something with umask and a startup script, but I'm not sure there's a startup script that will apply to connections via Finder. I also need this to apply to files created on a client (also Macs) and copied onto the server.