This time around, I'd like to highlight the new features and functionality exposed by iPhone Software Update 2.0.
When browsing the Web with Safari, you can now save images to the iPhone. Saved images are placed in the Camera Roll folder in Photo Albums and can be synched back to your PC.
When using the iPhone's Calculator application, you can switch to a new scientific calculator by rotating the device into horizontal (landscape) mode.
The Contacts application now supports contact searching.
International keyboard support
By default, the iPhone is configured to use a single virtual keyboard layout (English in the US). But you can enable other international keyboards if you'd like, including some character-based languages.
To enable an alternate keyboard layout, click the globe icon on the bottom left. Here's English, French, and Japanese.
PowerPoint Presentation viewing
While the original iPhone software supported just Microsoft Word and Excel viewing, iPhone Software 2.0 adds PowerPoint. Note that this is view-only, with no editing support. Also, large presentations, like the one shown below, crash the iPhone pretty quickly.