Making International calls to mobile

Hello guys,
I just learn about Asterisk, I m new in it. I have some experience in Linux and planning to dual run linux with my windows 7 laptop. Also I have some backgroung in teleommunication system
My questions is:
I have At&t Uverse phone (unlimmited US national call) and internet to be precise. I would like to know if it is possible to use Asterisk and make international calls to mobile for personal use without adding extra charge to my current phone and internet bill.
Thanks in advance for any help!

Yes, but there will normally be an extra charge to an ITSP!

What business model do you think would support the making of free outbound calls to the PSTN? Even if the destination country allows free local calls, the person providing the service still has internet, hardware, and line rental costs to recover from someone.

David55 since I am already paying for the landline phone thus I am already paying for the PSTN charge. The extra charge should be the VOIP charge since I have only regular internet. My point is can I connect my landline phone to Asterisk and make international mobile call for the price of a US national call?

Asterisk isn’t a service provider, it’s an enabling software.

Charges for international calls are at the discretion of your telephone company - whether that’s a traditional landline telco or a telco that you reach via VoIP. You might be able to find a VoIP provider that offers international rates to the locales in which you’re interested for what you pay for local calls to your current provider, but it’s your job to find them.

Since VOIP goes through a Packet-switch instead of a Circuit-swicth so I should not worry anyway about PSTN in the US ( forgetting about my landline). Can the VOIP through Asterisk be routing to the PSTN of the oversea country in order to route it to the mobile I am contacting? The cost of using that PSTN is on the mobile on the other end. Plus the country i am trying to call, Carriers don’t charge fee for incoming call. It is totally free to receive call there.

Asterisk can route a VoIP a call to a VoIP-PSTN gateway (or any other VoIP-PSTN box) that is oversees. But you are the one who need to set up both ends, so you can make those calls.

Thanks guys for the help. I understand Asterisk concepts now!