>How do I add it as a web reference?
>
>Right click on Reference.
>Select Add Web Reference
Yes.

>When the Add Web Reference box comes up, what do I put in the address bar?
Type the URL where the the web service it located. For example http://localhost/mywebservice/mypage.asmx or http://otherbox/mywebservice.asmx

>I don't see how I can get to the DLL. Am I supposed to add the asmx page?
You don't want to get to the DLL. You want the ASMX.

Remember that web services are accessed through HTTP, that's why you want to call the ASMX file (which is a web page in disguise)