QuickTime is a multimedia technology developed by Apple Computer, capable of handling various formats of digital video, sound, text, animation,
music, and immersive virtual reality panoramic images. QuickTime 7
offers a step into the next generation with support for H.264
high-definition video playback, surround sound, and many more exciting
QuickTime 7.1, which was released for Mac OS and Windows, delivers numerous important bug fixes and addresses
critical security issues, support for iLife "06 (under Mac OS),
and H.264 performance improvements. This update is highly recommended
for all QuickTime 7 users.
Both Windows and Mac OS users can download the standalone installer; however, Mac OS users can obtain the update via Software Update.
Download: QuickTime 7.1
News source: Mac Rumors