After the release of OS X 10.7 Lion this morning, Apple has released a few software updates to bring some of its applications up-to-date to work well with the features that Lion has to offer. These features include the option to run applications in full-screen mode, automatically save versions of documents and make them available through the document's title bar, and support Lion's Resume feature so windows and applications can be relaunched in their current state after restarting or logging out.
The updates are for iWork, available as a 79.66MB download through the iWork support page, and for iTunes, which brings the versions to 9.1 and 10.4, respectively. The iTunes update is available both for OS X and Windows, and weighs in at about 75MB to 90MB, depending on what version you are downloading.
While you can download standalone installers for these updates, they should be available through Apple's Software Update utility as well. In addition, even though they are tailored for the features of Lion, iWork requires at least OS X 10.6.6, and iTunes requires OS X 10.5 or later.
The iTunes update is the first to bring a full 64-bit Cocoa-native version of the application to OS X. As a result some plug-ins and add-ons for the program may not work, so be aware that after updating you may need to update these add-ons as well.
As always, be sure to fully back up your system before applying these updates. If you have installed Lion, make sure to have a full system backup completed before installing the updates, as any previous backups you have might be of Snow Leopard.