And yes, it breaks the iPhone "jailbreak" applications, despite not mentioning it:

This document describes the security content of the iPhone v1.1.2 and iPod Touch v1.1.2 Updates, which can be downloaded and installed via iTunes.

iPhone v1.1.2 and iPod Touch v1.1.2 Updates: ImageIO

Impact: Viewing a maliciously crafted TIFF image may lead to an unexpected application termination or arbitrary code execution.

This update is only available through iTunes, and will not appear in your computer's Software Update application, or in the Apple Downloads site.

There's a lot more going on in this download. It adds a cool charging icon in iTunes so you can see the status of the device's battery. You can actually create events in the device Calendar app now (what a concept). And more international languages are supported.