MCI Communications Corp. on Wednesday signed off on its venture with News Corp. and will invest an initial $1 billion in the deal that will link the two global giants in certain alliances. The two entities are expected to announce within a few weeks their plan to combine the efforts of News Corp.'s Delphi Internet Services Corp. and MCI's internetMCI operation. Separately, MCI will lay off 3,000 employees as a result of company restructuring.