Thanks to Sean Roberts for posting this on his blog. Below are the steps required to add a SQL Server Reporting Services 2008 Web Reference to your Visual Studio application.

1. Right click on your Project and then choose  Add Service Reference
2. Click on the [Advanced] button
3. Click on Add Web Reference
4. Paste in the URL from your web service and at the end add /reportservice2005.asmx?WSDL
5. For example http://yourserver/reportserver/reportservice2005.asmx?WSDL
6. Click the [Go] button
7. Click [Add Reference]

A little background is required here. Apparently, the reportservice2005.asmx file was left over, possibly for backward compatibility. That is why you need to specify that even though you are using SSRS 2008.

With the Web Reference in place you can now interact programmatically with your Reporting Server.

Thanks Sean!