Is this an ISO of a DVD?
You will need to 'rip' the DVD first to AVI (DivX, XviD) or another format.
UltraISO can open the ISO (to extract the DVD files)
VirtualCloneDrive (free) can mount the ISO so you see it as you would a DVD
AutoGK (free) can rip
Super (C) (free) can rip; can rip straight to the format that YouTube uses