In order to help, could you give a few more information please?
Like your skills, and why do you need website or if a VoIP server could do the trick?
Mastering VoIP can be a big deal so depending on your skills you'll have various solutions from renting a ready-to-use VoIP-oriented server, install a solution on a classical server, or up to develop it by yourself...
A little search around VoIP and I found voip-info.org, great help!
It provides, among others a list of VoIP Service Providers as well as a list of free SoftPhones solutions, which you could maybe use the code in your own..?
i am php developer and i want create something like Skype but in site
The first thing is it's important that rented voip server or vps or can I use the VOIP Providers,
If i use VOIP Providers i suppose that the cost will be Low to see Skype, for example, offers the service free