oauth and jason PHP app

We require a app which can do following things on freelancer odesk guru elance tasks the app should do post job query freelancer/companies based on some criteria and invite them for our project check messages received against projects reply to messages query jobs by keywords dowload and check the profile of the job poster apply for a job with amount/hourly rate, estimated time Please only apply if you have good knowledge of oauth and jason on above freelancer sites. if you can show sample code for above api, will be easy for us to assign the project to you.