Security Certificate on my local development box???

I had success recently in developing a Web Service for my company.

Now we are trying to push the service to the next level by adding security.

In that effort I was charged with creating the client to consume the service in a web application.

The Service programmer has provided me with what appears to be a cert.

What do I do with this cert? I have updated the wsdl in my WebReferences to refer to the new https:// version of the service.

I suppose I need the cert installed for anything to work? Now when I try and run the app as is the server cannot be found error message appears.

I am running on Windows XP Pro 2002 sp2..

See if this helps:
http://support.microsoft.com/kb/307267