Coding with the web services (lists.asmx, etc) have largely been deprecated. From the beta sdk:
Avoid Using SharePoint Data Providing Web Services
Earlier versions of the SharePoint Foundation product have provided a set of Web services to enable client interaction with SharePoint Foundation deployments. Some of these services, such as List Data Retrieval Web Service, are still supported, in order to provide backward compatibility and interoperability with Web service clients. For best performance and usability, we recommend that you use either the client object model or the ADO.NET Data Services Framework.