Someone knows some app what can call to mobile phone like a webphone.... I found jssip or sip2sip but i can't put into operation. This is for a telemarketers company
Unless you're benefiting from some first-time registration bonus, any call to a mobile phone will not come for free. In other words, you must seek to create some kind of account on an online VoIP service (e.g. Localphone, Skype, etc.), and top it up with some credit. In some cases, you may get away for free with the first couple of mobile phone calls, but not much past that.
After you're done setting up your account, you can plug the account's details (provider host, username, password) into either a free SIP mobile app (e.g. Blink, Zoiper, Bria, etc.) or even a SIP web app and starting using the credit you topped off the account with by dialing internationally, or locally for free.