Creative Mac has an interview with Frank Casanova on Quicktime 6 and MPEG4. Of note, it appears Quicktime 6 will incorporate the MPEG-4 standard:
NAGEL: Everybody's talking about MPEG-4 right now, but what's going on with that?
CASANOVA: ... QuickTime 5 does not have anything to do with MPEG-4. So right now, our version of QuickTime that's being distributed--a million copies every few days--is massively popular, but it remains separate from our MPEG-4 development. We have, though, seeded an early version of QuickTime that has MPEG-4 built in to a set of key developers. And they've had this code for upwards of a month now. This software is letting them start testing the next release of QuickTime with MPEG-4 support and see how it fits into their applications and make sure everything works just fine.
NAGEL: Everybody's talking about MPEG-4 right now, but what's going on with that?
CASANOVA: ... QuickTime 5 does not have anything to do with MPEG-4. So right now, our version of QuickTime that's being distributed--a million copies every few days--is massively popular, but it remains separate from our MPEG-4 development. We have, though, seeded an early version of QuickTime that has MPEG-4 built in to a set of key developers. And they've had this code for upwards of a month now. This software is letting them start testing the next release of QuickTime with MPEG-4 support and see how it fits into their applications and make sure everything works just fine.