iPhoneDrive ($9.95), from Ecamm Network, allows you to use your iPhone for file storage, something you can't do with Apple's iPod/smartphone combo out-of-the-box, as there's no disk mode for iPhones like there is for iPods.

Launching iPhoneDrive brings up the utility’s browser window and toolbar. It is from there you can transfer files and folders back and forth between your Mac OS X computer and iPhone.

There are two ways to perform transfers to an iPhone: Drag and drop content from the Mac Desktop or a Finder window into the iPhoneDrive browser or click the "Copy To iPhone" button on the toolbar.

To do the reverse, you can either click the "Copy From iPhone" button on the toolbar to move highlighted files or folders to a location of your choosing on the computer; drag content directly from the iPhoneDrive browser window into a Finder window or onto the Desktop; or simply double-click a file to download it to your Documents folder.

With iPhoneDrive, you can also create folders on and delete files or folders from your iPhone.

You can't view content you've transferred from your computer on the iPhone with iPhoneDrive, however, as the software is for storage purposes only.