Dear Concern,
Payment is negotiable...
I am haing 2.5 years of experience in web development with PHP,
i have worked on PHP 3 to 5.2.3,
In order to implement webservices with PHP first of all you have to provide the version of PHP, because the version is 4 then there is no problem because its inbuilted support for Webservices with WSDL 2, SOAP 1.1, 1.2 as well, so that if we make the WSDL for your service then it hardly takes around 2 to 3 hrs to handle with code,
please get more in detail about your server, and what type of webservice you need proceed with ? REST based or SOAP --> If REST means then its not a big deal to finish it of by a day.