Never thought of listing all TFS 2008 Web Services before until I needed to start access them directly.
Below is the full list of Web Services which comes in two versions, V1.0 and V2.0 for backward compatibility I believe ...
Build Service
V1.0
V2.0
Services Service
V1.0
http://YourTFSServerName:8080/Services/v1.0/AuthorizationService.asmx
http://YourTFSServerName:8080/Services/v1.0/CommonStructureService.asmx
http://YourTFSServerName:8080/Services/v1.0/EventService.asmx
http://YourTFSServerName:8080/Services/v1.0/GroupSecurityService.asmx
http://YourTFSServerName:8080/Services/v1.0/ProcessTemplate.asmx
http://YourTFSServerName:8080/Services/v1.0/projectMaintenance.asmx
http://YourTFSServerName:8080/Services/v1.0/Registration.asmx
http://YourTFSServerName:8080/Services/v1.0/ServerStatus.asmx
V2.0
Version Control Service
V1.0
Warehouse Service
V1.0
WorkItem Tracking Service
V1.0
http://YourTFSServerName:8080/WorkItemTracking/v1.0/ClientService.asmx
http://YourTFSServerName:8080/WorkItemTracking/v1.0/ConfigurationSettingsService.asmx
http://YourTFSServerName:8080/WorkItemTracking/v1.0/ExternalServices.asmx
http://YourTFSServerName:8080/WorkItemTracking/v1.0/Integration.asmx
http://YourTFSServerName:8080/WorkItemTracking/v1.0/SyncEventsListener.asmx