HI, Gerard, one more thing..as Viv correctly mentioned, you want to change the target framework to 3.5.

At that point, that might be all you need to get started.

If you need a refresher, here are a few links you can use....

http://sarangasl.blogspot.com/2010/09/create-simple-web-service-in-visual.html
http://msdn.microsoft.com/en-us/library/ms464040.aspx
http://msdn.microsoft.com/en-us/library/8wbhsy70.aspx

(Note, one of those uses a web service that's involved with SharePoint, but it still has some good tips. But if you're able to get what you need from Viv's advice, then the links might not be needed for you).