I\'m trying to connect to TFS 2010 using TFS SDK, but can\'t get VersionControlServer service.
var servers = RegisteredTfsConnections.GetConfigurationServers
You don't want the configuration server, you want the project collection. The version control service is scoped to a team project collection. For example:
var projectCollection =
TfsTeamProjectCollectionFactory.GetTeamProjectCollection(registeredProjectCollection);
var versionControl = projectCollection.GetService<VersionControlServer>();
See also: Connect to a Project Collection