Apple released another Quicktime update, version 7.6.2. This update applies to Mac OS Xv10.4.11, OS X v10.5.7, Window Vista and Windows XP SP3.   It looks like the update takes care of 10 vulnerabilities.  All of the vulnerabilities stem from viewing a maliciously crafted movie or picture file. 

support.apple.com/kb/HT3591

support.apple.com/kb/HT3520

The second link says that this update includes changes that increase reliability, improve capatibility and enhance security. It also says that this update improves the compatibility with Apple ProRes media and improves ITunes support.  (Interesting that they bundled these in with a security update). 

Make sure that you pay attention to the updater.  It looks like there are 2 choices for the update.  Just the update or the update and ITunes.  If don't have ITunes it looks like it would install it.