Apple has announced that Quicktime has various security update.
Java for Mac OSX 10.5 Update 1. This update does not replace the existing installation of J2SE 5.0 or change the default version of Java. Better improvements on security and memory usage.
On April 24th, Apple released new bootcamp update for Windows XP, Windows Vista 32, and Windows Vista 64. It includes many fixes and recomended for all Bootcamp users.