Finally, a way to access some documents on the device directly through USB, without having to e-mail it to yourself!
Plus, it looks like you can now choose which app opens up when you open up a file, like open and edit iWork e-mail attachments in the proper iWork app, or choose to just view.
Applications that want to share files with the user can now do so using the file-sharing support in iPhone OS 3.2. Heres how it works:
1. An application indicates that it wants to share files.
2. It puts whatever files it wants to share in its Documents/Shared directory.
3. When the device is plugged into the users computer, a mount point is added to the system and the contents of any shared directories appear on the users desktop.
4. Users can modify the contents of this directory freely by copying files out, deleting files, or dragging new files in.
An application can now register the file types it supports with the system and receive notifications when a file of the given type needs to be opened. An application that registers one or more file types may also be expected to open files of those types at some point later.
I should add that as of now Apple says iPhone OS 3.2 is for the iPad only, and doesn't say when or if it will ever be available to other devices. I'm hoping this same stuff gets added to the iPhone and iPod touch in 3.2 or 4.0 though.