.NET WCF web service VB.NET

I need a WCF web services project creating in Visual Studio that will allow an iOS app to communicate with a sql server database via JSON. The web services needs to allow the following key features: Use the data held in a user table to allow users to login Retrieve data from a table of tasks/jobs and show correct data, based on who the logged in user is, and the current date Allow the logged in user to write data back to the jobs/tasks table There are more details which I can give to the winning bidder. The sql server database is already created and online, there is a current .net application that operates as the back office system. The webservices I need creating are to allow a mobile device to transfer data from the the web server to a local sqllite database on the device.