There are two ways to go about this. You can either use the IDE to generate a WSDL, or you can do it via the command line.
1. To create it via the IDE:
In the solution explorer pane, right click on the project that you would like to add the Service to:
Then, you can enter the path to your service WSDL and hit go:
2. To create it via the command line:
Open a VS 2010 Command Prompt (Programs -> Visual Studio 2010 -> Visual Studio Tools)
Then execute:
WSDL /verbose C:\path\to\wsdl
WSDL.exe will then output a .cs file for your consumption.
If you have other dependencies that you received with the file, such as xsd's, add those to the argument list:
WSDL /verbose C:\path\to\wsdl C:\path\to\some\xsd C:\path\to\some\xsd
If you need VB output, use /language:VB in addition to the /verbose.