Only the 466MHZ Clamshells were equipped with a DVD drive, although the 366MHZ firewire Models are capable of playing DVD movies too if you connect a DVD drive instead of the CD-ROM. You will a face a few dropped frames, but because of the the 8MB ATI graphics you can use the Apple DVD player which is integrated in OSX because it meets its minimum requirements.
If you can tolerate skipped frames try the VLC Freeware video player with your 300mhz or 366mhz iBook (non-firewire). You better play your movies directly from the harddisk and allow VLC 15 seconds to synchronize video and audio, at fist sight you will get a scambled output.