Note: This was our initial coverage of the announcement. It's now a news story on the main ADN homepage. That story will be updated through the afternoon.

From Sean Cockerham in Anchorage and Erika Bolstad in Washington –

The pipeline company TransCanada announced today that it has an agreement with Exxon Mobil Corporation to work together on an natural gas pipeline from Alaska to the Lower 48.

“We are pleased that TransCanada and ExxonMobil have reached agreement on initial project terms to progress this exciting initiative," Hal Kvisle, TransCanada president and chief executive officer, said in a written statement.

The statement contained no details but the companies have scheduled a noon teleconference (Alaska time) with reporters to discuss it. Some Alaska state legislators were briefed by TransCanada this morning, and at least one emerged highly skeptical about the importance of the development.

An agreement was reached this week between TransCanada and ExxonMobil to partner together in building Alaska’s natural gas pipeline. Governor Palin, center, is joined in Dallas, Texas this week by (left to right) Marty Massey, Joint interest Manager for Exxon Mobil; Alaska Department of Natural Resources Deputy Commissioner Marty Rutherford; Rich Krueger, President of Exxon Mobil Production Company; Hal Kvisle, President and CEO of TransCanada Corporation; and Dennis McConaghy, Executive Vice-President of Pipeline Strategy and Development. Photo courtesy of the Governor's Office.

Exxon isn't talking, other than to say that some of the details provided by state legislators about the deal aren't totally accurate. What's happening seems to depend on who you talk to. “My take is what’s going on here is a completely overblown media circus,” said Anchorage Rep. Mike Hawker.

Anchorage Sen. Lesil McGuire told the Associated Press that Exxon will become an equity partner in TransCanada Alaska Co. but has not agreed to state licensing terms. Exxon will make a $150 million capital investment in the company, which has been licensed by the state, McGuire said.

The governor's office put out a press release saying the "must haves" under the Alaska Gasline Inducement Act won't be changed as the result of the deal. Gov. Sarah Palin said in the statement that " Alaskans will also be pleased to know that TransCanada’s obligations to the state as the AGIA licensee are 100 percent intact and unaltered by this alignment with ExxonMobil.”

The governor's office described it as a "historic agreement."

Rep. Hawker said that the companies will announce the formation of an “integrated project team.”

“The way it’s been explained to me is that all this project team is, is they’ve hired Exxon Mobil Corp to do the front end development work on the gas treatment plant which is something TransCanada doesn’t do. That’s oil industry technology, that’s not pipeline technology,” he said.

Hawker, whose wife works for the competing oil company Conoco Phillips in its Cook Inlet operations, said TransCanada is basically hiring Exxon as a subcontractor.

“Exxon will pass its expenses back to TransCanada, TransCanada will bill half of them back to the state of Alaska,” he said.

Under the terms of the Alaska Gasline Inducement Act, the state has agreed to reimburse TransCanada for up to $500 million in costs.

Hawker said that he understands the idea is for the companies to do more together in the future, but at this point there are no commitments other the gas conditioning plant work.

Meanwhile, the entire congressional delegation has been on the phone today with Gov. Sarah Palin, who hinted the deal was coming on her Twitter page: "Appreciate Sec. Salazar, Sens Murkowski & Begich, Rep Young - this morn we discussed need for Ak's natural gas to flow into hungry markets."

Palin also had a conversation about the pipeline project this morning with Interior Secretary Ken Salazar, his spokeswoman said.

Reuters has some additional details, and yesterday’s Houston Chronicle story covers many of the basics of the proposal.