External USB DVD-ROM on 333Mhz iMac?

Well, although a video DVD theoretically needs 11Mbit of data, which USB1 can supply, I don't think you'd be able to watch video anyway--if memory serves, earlier G3s like the iMac you're talking about needed hardware help to play a DVD, which wouldn't be supported.

There is a hack to try and help computers that old play DVDs:

http://www.xlr8yourmac.com/OSX/OS_X_10.1/OS_X_DVD_player_mod.html

...but reports there say that you'll probably have trouble on anything less than a 400MHz G3, so I wouldn't get my hopes up.

The only bright side is that an external USB case only runs around $40, and a drive can be had for $60 or so, so it's not a huge expense to try. Then again, if you have the space, you can get a cheapie TV and DVD player for not a whole lot more than that.

 

I've never heard of anyone getting this to work.

And frankly, considering how cheap DVD players are, do yourself a huge favor and just get one for yout TV. Lacking a Tv, then a DVD/TV combo can be had pretty cheap too. it'll be os much easier, and probably about the same in terms of cost. Plus, watching a movie on TV is infinitly better than watching on a computer.