Where is 'file sharing'?

I might be wrong, but I think some apps do the file sharing.
Files shows up as a file sharing, but I normally transfer those files wirelessly. Maybe Stanza, iBooks or another app has to be installed to show and be used.

This "File Sharing" is the name of an app? If you don't already have it, you have to go to the iTunes store and buy it.

File Sharing lets you transfer files between your iPhone, iPad or iPod touch and your computer. You can share files created with a compatible application and saved in a supported format.

Applications that support file sharing appear in the File Sharing Apps list in iTunes. For each application, the Files list shows the documents that are on iPod touch. See the application’s documentation for how it shares files; not all applications support this feature.

When you have installed an app that supports file sharing, the file sharing section will appear in your iTunes apps tab as shown here:



The instructions for using file sharing are on page 60 of iPhone iOS4 User Guide

The File Sharing section is located at the bottom of the Apps pane in iTunes when your phone is connected If you have Apps that support it. It allows access the the data directories for those apps. Looks pretty limited but could function.
Most apps that store data seem to have pretty god sync and transfer features built in.
I don't think it will work to turn the phone into a flash drive. One app, QuickOffice lets you log in to it over a any network from any web browser. This one works really well. I sue this all the time on consulting jobs.