Bill Parise the agent for James Harrison has told Inside Pittsburgh Sports this afternoon that the Steelers, Harrison will hold a press conference on Tuesday to announce the two sides have agreed to a long-term extension. A deal was finalized this afternoon.
The deal is worth

$51.7 million over six years (updated: 4/13/09). Both sides made concessions but would not confirm the amount of guaranteed money Harrison will receive.
I will have more on this later this evening.