If you’re looking for a DVD player, whatever OS you are running, have a look at VLC.
Not only this piece of software will read any DVD, regardless of the region code, but it also runs on all sorts of OS like Windows, Mac, Linux, BeOS, Solaris, Zaurus, etc..
Even better: it’s not only a player, it can also be used as a source to broadcast video over the LAN (or at least a network with large bandwidth capabilities) via multicast!
Oh, and did I tell you that everything is free?…