PhoneDisk lets you mount your iOS devices on your Mac, so that you can use them as external disks. The application can be downloaded for Windows as well, so you can use it to move files between your computers, or to download your photos, videos, ringtones, etc.
Unlike other similar apps, PhoneDisk runs on the MenuBar and it can detect iOS devices, when they are connected to your Mac. When that happens, the application automatically mounts it on Finder, so that you can access it from there or any other app on your Mac.
I have recently used PhoneDisk to send photos to my iPad so that I could share, and the process was very straightforward. By default, your devices show their root directory, but you can change this from the MenuBar to show the Media folder only, which gives you quick access to the DCIM folder on your iOS device.
When I installed PhoneDisk, the app didn't run well right away. There was a problem with MacFUSE. Somehow system restart solved the problem.
All in all, this is a great tool to have if you frequently use your iOS devices as external drives. Having the app automatically mount drives saves you lots and lots of time.