BILLINGS -- State Sen. Roy Brown, R-Billings, said Monday he is a candidate for the Republican nomination for governor in 2008.

He is the first GOP candidate to announce a challenge to Democratic Gov. Brian Schweitzer, who has announced a re-election bid next year.

Brown will formally announce his candidacy on Thursday with a six-city fly-about and a 50-towns-in-10-days ground tour beginning Monday.

Elected to the Montana Senate in 2006 after serving four two-year terms in the Montana House, Brown has held several GOP legislative leadership posts.

He said he was "compelled to run because state spending is completely out of control."

The budgets in the past two legislative sessions have increased more than 40 percent, he said.

"If there is a blip in the economy, the taxpayer-funded surpluses will not be there to fund the new spending," he said. "There are automatic escalators written into those spending increases. That means there will be calls for tax increases and history says that does not work."

The Montana budget for the 2009 biennium that began July 1 is $9.04 billion, with state general fund appropriations for the two years at $3.78 billion. That total includes $80 million added in the special session for firefighting costs, according to the office of the legislative fiscal analyst. The difference between the total budget and the general fund budget represents federal money such as Medicaid matching funds to the state and special accounts.

A retired oilman, Brown, 56, owns and manages rental properties in Billings. He received a bachelor's of science degree in petroleum engineering from Montana Tech in Butte in 1974.

Advancing a four-point program, Brown said he will work for long-term, real property tax relief; elimination of the business equipment tax now frozen at 3 percent; a return to accountability and integrity in campaign finance and openness in government; and the enactment of responsible state spending.

"I'll be promoting Montana, not myself," Brown said with a smile, a not-so-subtle reference to Schweitzer who has traveled extensively since taking office in 2005. He has been visible on the national stage promoting the use of Montana natural resources, especially the use of coal and clean-coal technology.

Schweitzer is in Alberta, Canada, for a two-day visit with provincial leaders and energy-related businesses. He returns to Helena today.

Brown said the decision to run was "an extremely difficult process." He said his wife, Kim, and their three children are all on board and excited about the coming campaign. He said he does not expect an opponent in the primary election, "but anything is possible."

Raising money in an election year that features campaigns from the White House to the courthouse, Brown said he expects to raise and spend $1.6 million.

"It will be difficult, but if I can get 16,000 people to give me a hundred bucks, that is $1.6 million." State law allows a candidate for governor to accept donations of up to $500 per individual for both the primary and general elections.

Montana's primary election in 2008 is June 3. The general election is Nov. 4.

The Thursday announcement tour begins in Billings at 8:30 a.m. in the Peaks to Prairie Park next to the big bell on the Montana State University Billings campus. The daylong tour has stops in Helena, Great Falls, Kalispell, Missoula and Bozeman before returning to Billings Thursday evening. The road tour on Monday heads into Eastern Montana and then swings to the western portion of the state to hit the areas not touched in the fly-about.

"It will be the first of many," Brown said of the road trip. "I want to gather the public's take on how things are going. I want to get a feel for the state as a whole."

Brown served as House majority whip in 2001, majority leader in 2003, and House Republican leader in 2005 when there was a 50-50 split of the chamber.

A holdover senator in Senate District 25, Brown was elected to a four-year term in 2006. In that election, he turned back a concerted effort to defeat him. Brown said his opponent, Democrat Margie McDonald, and her supporters spent almost $100,000 during the campaign; he spent $39,000.