Step 1:
Start--> Programs-- >Microsoft Visual Studio 2008-- > Microsoft Visual Studio 2008.
Step 2:
File-- >New Project-- >Web-- >WCF Service Application-- >Name the Solution (e.g. MyFirstWCFApplication) and Save.

It will generate following Files structures.


Step 3:
Click on Default file named (IService1.vb). It creates default
1.

' NOTE: If you change the interface name "IService1" here, you must also update the reference to "IService1" in Web.config.

_
Public Interface IService1

_
Function GetData(ByVal value As Integer) As String

_
Function GetDataUsingDataContract(ByVal composite As CompositeType) As CompositeType

' TODO: Add your service operations here
End Interface
2.
' Use a data contract as illustrated in the sample below to add composite types to service operations.
_
Public Class CompositeType

Private boolValueField As Boolean
Private stringValueField As String

_
Public Property BoolValue() As Boolean
Get
Return Me.boolValueField
End Get
Set(ByVal value As Boolean)
Me.boolValueField = value
End Set
End Property

_
Public Property StringValue() As String
Get
Return Me.stringValueField
End Get
Set(ByVal value As String)
Me.stringValueField = value
End Set
End Property
End Class


Note:
1. In _ there is one Interface named IService1. This may be changed.
2. Each _ having Interface may have multiple Funtions preceded with _.
3. Add the Functions like to invoke or Expose.
3. All defined or renamed Interfaces references must be updated in Web.config file.





























4. In _ there is one CompositeType class. Inside _ there are many _ which is nothing but the Property of the class used to expose to the outer world. Each Property must precedded with _ else it will not be exposed.








Step 4:
Now Click on Service1.svc.vb a class file that Implement s the defined Contracts. Define the function defined by Interface and save this file.
Step 5:
Build the application.
After Building the application this Application can be used by Client Applications in different ways.
1. By Adding Service reference Locally
2. By Hosting it on IIS