Download and install the Skype application from the App Store on your iPhone.

Tap the "Skype" icon on the iPhone's home screen, and enter your Skype user name and password into the appropriate fields. If you are new to Skype, touch the "Create Account" tab at the bottom of the screen, tap "Accept," and enter your full name, Skype name and password into the fields. Enter your email address, and tap the "Done" button to finish the account creation.

Tap the "+" button in the upper-right corner of the screen, and tap "Add Phone Number" to enter a new phone number into the Skype application. Alternatively, tap the "Import from iPhone" tab after tapping the "+" icon to import a contact from your iPhone's address book, and tap the number to import it. Tap "Save" to save the number to the Skype app.

Tap the contact name in the "All Contacts" screen, and tap the "Call" button to place the phone call, or tap the "SMS" button to send a text message to the contact.

Touch the "Call" icon at the bottom of the screen, and enter the phone number you wish to call, starting with the area code. Touch the green "Call" button to place the call.