There is a known (but already patched) vulnerability the affects the following versions of Apple OSX and Quicktime:
Apple QuickTime Player 7.6.5
Apple QuickTime Player 7.6.4
Apple QuickTime Player 7.6.2
Apple QuickTime Player 7.6.1
Apple QuickTime Player 7.6
Apple Mac OS X Server 10.6.2
Apple Mac OS X Server 10.6.1
Apple Mac OS X Server 10.6
Apple Mac OS X 10.6.2
Apple Mac OS X 10.6.1
Apple Mac OS X 10.6
BUT this has already all been patched in the latest Apple 10.6.3 update. Therefore, if you didn't update your Apple OS last week, please go ahead and do so without delay.
Products that are NOT vulnerable are:
Apple QuickTime Player 7.6.6
Apple Mac OS X Server 10.6.3
Apple Mac OS X 10.6.3
The news here is to always stay current with all software updates.