I am creating SharePoint Team Sites using SharePoint Web Services as I cannot use the object model for this solution (I do not have SharePoint installed on the server where the sites are created from). The sites create fine but I do not have the default "Members", "Visitors" and "Owners" groups. I know using the SharePoint Object Model you can use the SPWeb.CreateDefaultAssociatedGroups method. How would you be able to perform a similar operation using SharePoint Web Services?
Assuming that you mean the SOAP or .asmx Web Services, I don't think that the option you want is exposed in any of the available operations.