While you can use your iPod as a portable hard disk, Apple does not allow you to transfer files to/from your iPhone. Although there are several apps that allows you to copy files, they are no free solutions. If you have jailbroken your iPhone, you can customize it to connect to the desktop and copy files to/from your iPhone.
For those who have not jailbreak their iPhone, here is a tutorial on jailbreaking your iPhone the easy way.
For Mac users:
In Mac, you can make use of AFP to access iPhone/iPod Touch via the Finder.
To do this, you have to first install Netatalk via Cydia.
On your jailbroken iPhone, go to Cydia. At the bottom, go to Sections. Navigate to Networking -> Netatalk. Click install on the top-right corner of the screen.
Once you have installed Netatalk, on your Mac desktop, open up Finder, you should find your iPhone entry on the left pane, under the ‘Shared‘ section. Click on it. You should see a blank screen with a ‘Connect As‘ on top of the screen.
Click on the ‘Connect As‘ and enter the following:
For some reason that you can’t find the entry in the Shared section, you can go to Go -> Connect to Server. Under the server address field, enter afp://your-iphone-ip-address. Mine is 192.168.0.102, so I entered afp://192.168.0.102. (You can find your iPhone IP address on Settings->Wi-Fi->Your network connection)
The Connecting to Server window should open up, and then ask for your user name and password.
Fill in the above login credential.
That’s it! You can now access the iPhone straight from Finder!
Most of your personal files will be in private/var/root/Library or private/var/root/Media. And of course installing applications is as easy as dragging the .app into your /Applications folder!
For Windows users:
iPhoneBrowser is a windows based file browser for your iPhone. It features drag and drop uploading to our phone, automatic and manual backups of files on your phone, previews of text and picture files and very cool icons.
Download SetupiPhoneBrowser.1.7.exe from http://code.google.com/p/iphonebrowser/downloads/list
Run the installer on your Windows XP (May not work well on Vista).
Upgrade your iTunes to 7.7.1 (it works on iTunes 7.7 as well).
Open the iPhoneBrowser and connect your iPhone to the computer via the USB cable. The iPhoneBrowser should detect the iPhone and show the file structure on its screen.
You can now drag and drop files to the iPhone.
For Linux users or any other platforms:
In any platforms, as long as you have a FTP program, you can easily transfer files to/from the iPhone via OpenSSH.
On you iPhone, go to Cydia. Tap on Section on the bottom pane and scroll to Networking->OpenSSH. Tap on the Install button to install it.
On your desktop, open up your FTP program (it doesn’t matter which one you use. For me, I used Filezilla because it is free and easy to use).
On Filezilla, go to File->Site Manager
On the left, click New Site
Rename the site to ‘iPhone‘
On the right, enter the following:
Host: Your iPhone IP address
Servertype: SFTP – SSH File Transfer Protocol
You will be shown a confirmation message asking if you will accept key exchange / connection with the device with the iPhone’s address. You’ll need to click OK for it to connect.
Once connected, you will see the familiar Explorer-like navigation structure. Simply drag and drop the files to and forth the iPhone.