First, you should know that Apple seeded a new build for Mac OS X Leopard Server 10.5.3, labeled 9D25. This new build fixes a handful of bugs, such as various issues with the Mail and Web Server components, the Server Assistant, and Slapconfig, but the best part is that rumors say we should get the 10.5.3 version finalized within the next two weeks.
Yesterday, the ATI Radeon HD firmware got updated, bringing the current version to 1.0.1 and increasing stability for those using the Radeon HD 2400 XT or Radeon HD 2600 Pro. The 848KB update can be downloaded from the Apple website, of course.
Java for Mac OS X Leopard also got an update, which installs Java SE 6 1.6.0_05 for all compatible Macs. The Java for Mac OS X 10.5 Update 1 is also available on Apple.com, of course. Just click the link above and you'll end up on the official product page.
At last, it should also be noted that Microsoft released Messenger for Mac 7 with video. Since this is not a release from Apple, I won't get into it. After all, you have the link above, so you know what to do...
Well, this is it for today, I hope at least one of the updates above proves to be useful to you and you won't have any problems while bringing your software up to date. Good luck!