Children of the mind - Orson Scott Card

A PLANET LIES OPEN TO ATTACK. THERE IS STILL HOPE - BUT TIME IS RUNNING OUT

The Starways Congress has gathered a fleet to destroy the planet Lusitania. Once again the human race has grown fearful.

Jane, the evolved computer intelligence, can save the world' three sentient races. She has learned how to move ships outside the universe, and then instantly back to a different world, abolishing the light-speed limit.

But it takes all the processing power available to her. With Starways Congress shutting down the Net, world by world, soon Jane will not be able to move the ships. Ender's children must save her if they are to save themselves.