Just to comment on this particular thread - Although it is necessary to have a DVD-ROM, or, better yet, the new SuperDrive, to read and play a DVD movie, you don't necessarily NEED a hardware decoder to play them.
I know of at least one Mac software-based DVD-player. The performance isn't top-notch, but its still in beta. It requires a fairly recent and fast processor, I belive they recommend a 300 at the VERY least, and movies don't play particularly in sync on my B&W 350. That was when I had 128 MB of RAM, now I have 384, and haven't tried it again, because, well, I have the deocder hardware, so what's the point?
But I can say that this software DOES WORK - limitedly. As far as playing it back on a 233 iMac, I dunno. Perhaps future versions will be less processor intensive. I have no idea where I got this program, and I don't have it in front of me, but when I get the name of it, I'll post it up for everyone who's interested.
It has the tempting promise to allow a Mac user to buy a cheap PC DVD-ROM and not have to upgrade their video card, which, in the case of the 233 iMac, might be difficult to impossible to acheive. Also, with the new 466 MHz upgrade cards available for the iMac, this may be a very viable alternative.
-zjd
B&W G3 350, 384 RAM, OS 9.1/OS X PB
8600/300, 128 RAM, OS 9.1/8.1