Actually, that phone number will not get you a CAF#. You will need to file form 2848 or 8821 with your friend's information on it. After faxing these forms to the IRS, you can call ACS to verify that your POA was received. Once this has been established the IRS will automatically assign a CAF# to you based on the faxed POA and tax payer information. Never sign somebody's tax return, even if you have a 2848.