Having trouble playing back QuickTime movie files downloaded from my iPhone.

QuickTime constantly complains that it is missing codecs. So I guess it
needs H.264 for the audio and MPEG-4 for the video? That is what G-Spot
Appliance tells me.

What is the best source for codecs to play back these streams under Windows
ME or the best alternative workaround?

Thanks in advance!

Martin