Mac OS X 10.4.4 is now available for download via Software Update, following Apple CEO Steve Jobsi announcement of the update earlier today.
The highlighted fixes, as noted in Software Update, include:
Additional information on the Mac OS X 10.4.4 update is available here, while the 55MB download can be found directly on this page. (The updater via Software Update weighs in at a lighter download, depending on your system configuration.)
A Combo Updater for Mac OS X 10.4.0, 10.4.1, and 10.4.2 users is also available as a 120MB download.