Ecamm Network has updated its iPhoneDrive software (which allows you to drag and drop files between your phone and your computer) to include support for moving files around on your iPhone as though it were truly a portable drive.
You’ll also be able to drag multiple files off of your phone and an iTunes bug has been fixed as well.
The software goes for $9.95 until Apple decides to just enable this feature like it should have done in the first place.