First, make sure you have
AFP installed on the iPhone - you need
Installer. Turn on Airport on your Mac and
create network from the airport icon menu. If the network is set, you'll see the
airport icon changed. Set iPhone to
join the network you just created. Take note of the iPhone
IP address. On your mac, activate Finder. From the
top menu, choose Go > Connect to Server. Type you iPhone IP address like this
example. You will be prompt for
login. Type 'root' as user, and 'alpine' for password. Choose
Root's Home instead of Root Filesystem because the earlier has bigger disk space.
For what? iPhone as your wireless external disk drive.