working from overseas/ phone calls

[Jonathan Beemer]

Hi, i am working from overseas in italy and need to make phone calls back to the US. i only have an italian number, i have an iphone with the availability to download apps, etc. 
i need an app or something to allow me to use a US number to make calls from Italy back to the US.
i would like to use my italian phone and just be able to use a false american phone number. 
any advise?