The United States Secret Service has dispatched a protective detail to assume the immediate protection of Sen. Joseph Biden, D-Del., a source tells ABC News, indicating in all likelihood that Biden has been officially notified that Sen. Barack Obama, D-Illinois, has selected him to be his running mate. Sources also tell ABC News that two others said to be finalists for the position of Obama's running mate -- Sen. Evan Bayh, D-Ind., and Virginia Gov Tim Kaine -- have been told they have not been selected to be Obama's running mate. Kaine flew to Denver earlier today, is in Denver...