UPDATE, 4:58 PM SUNDAY: CNBC is reporting that Softbank will pay $20 billion for a 70% stake in Sprint, citing sources close to the deal. Although details are still being worked out, the deal is expected to be announced tomorrow morning after the boards of both companies ratify the agreement this evening. Terms of the deal call for Softbank to buy $8 billion worth of shares directly from Sprint at a price of $5.25 each plus tender for another $12 billion worth of shares from existing holders at a price of $7.30 per share. Sprint’s current price is $5.73. While a related Sprint purchase of Clearwire is not likely to be announced tomorrow, sources say the company is working on it and needs to insure Clearwire is under its control prior to closing the Softbank deal.

PREVIOUSLY, THURSDAY PM: Backfield’s in motion among the wireless and wireless broadband companies that have become so important to the infotainment industry. Talk that Softbank of Japan is negotiating to buy a controlling stake in Sprint Nextel sent the wireless phone company’s stock +14.3% today. And shares in wireless broadband provider Clearwire, where Sprint owns slightly less than half of the stock, soared 70.8%. CNBC’s David Faber reported that Sprint is negotiating to buy Clearwire, possibly in conjunction with its efforts to strike a deal with Softbank. What does all of this mean? That’s hard to say for the companies: Little is known about how much Softbank might pay, and whether it wants to invest in Sprint’s service or simply acquire its spectrum. But it might be bad news for Dish Network, which has been amassing spectrum for its own somewhat mysterious wireless broadband service. Chairman Charlie Ergen has been talking about the possibility of finding a partner and “the prospects for a deal with Sprint [if it teams with Softbank] would appear diminished, increasing the probability that Dish would need to build on its own,” Bernstein Research’s Craig Moffett says. And if Sprint buys Clearwire — which has been struggling to find its niche in the wireless market — then that “would result in increased direct competition for whatever it is that Dish Network plans to build.”