hi daniel,
I would suggest do create a DVD-ROM, not a VIDEO-DVD.
if these disc will only be played on computers you can choose to go HTML or maybe to start programming it with DIRECTOR.
on computers it doesn´t matter if you´re using PAL or NTSC-frame-rates, but if you need to create a VIDEO-DVD for international distribution you need to go NTSC. PAL-DVDs wont be played on NTSC-players but the other way arround will work.
it will be a good choice to create the video-files 2 times!
1.) mpeg4-files for mac-users
2.) wmv-files for pc-users
as most pc-users haven´t installed quicktime or itunes and most mac-users haven´t installed the wmv-playback-plugin for quicktime.
if you decide to create a DVD-ROM based on HTML you can choose FLV, too.
but be awared: a lot PCs have trouble with WMV-HD or FLV as they are real resource-consuming
cheers
danny