There's not much to getting a service reference to Web Services in GP 2010, but I can never remember the name of the service. I'll write it done here and have it at my fingertips.
To start, open Visual Studio 2010 and create a project.
In the Solution Explorer, right click on Service References and click on Add Service Reference
In the Add Service Reference dialog, type in the URL for the web service, which is Http://<machinename>:48620/Dynamics/GPService. Click on 'Go' to do the discovery. You should see something like the screen shot below. Give the web service a friendly name and click 'OK', you're all set.
