Besides Skype and yahoo voice is there any other way to make calls from pc to mobile phones internationally ?

You can use a SIP provider. You will most often need a software phone as well (there are some soft phones that are free, and some providers offer their custom made soft phone, too). Some providers also offer 'web phones' that you can use from your web browser.

Here is a brief article that you might find interesting to read. It talks about the differences between using SIP and Skype.

http://ezinearticles.com/?SIP-and-Skype---Differen...

You can take a look at that article and then begin to look for SIP providers in or near your area, or check the best known ones. When it comes to SIP, you might have to go through a learning curve if you want to do it yourself, but some companies offer products that work out of the box.

Good luck,

Marc