During a speech marking Martin Luther King Jr.’s birthday in Trenton, N.J., last month, Sen. Frank Lautenberg (D-N.J.) told the audience that freshman Sen. Barack Obama (D-Ill.) would attend a March fundraiser on his behalf.

“I mentioned that he would be coming to New Jersey and there was a sudden burst of applause,” Lautenberg said last week. “It was instant recognition.”

Lautenberg should consider himself lucky. Obama’s aides estimate he is getting 300 fundraising and speaking engagement requests each week — a dizzying amount for any Senator, much less one who has been in office for less than two months. But Obama isn’t any run-of-the-mill lawmaker. He is the first black American to serve in the chamber since 1998 — the year Sen. Carol Moseley Braun (D-Ill.) was defeated after just one term.

“He has broken a longtime barrier here,” Lautenberg said. “We don’t have a long history of African-American representation in the Senate.”

Across the aisle, the GOP’s version of a “rock star” is former Rep. John Thune (S.D.) who defeated Senate Minority Leader Tom Daschle (D) in the highest-profile Senate race of 2004. Now, it seems as if every Republican organization and fundraiser wants a piece of Thune.

Since being sworn in, Thune has received more than 700 invitations to appear at fundraisers, and other events such as Lincoln Day dinners.

“We have had a lot of requests from political parties in states, candidates, committees, all of the above,” Thune said.

Republican leaders are also seeking to capitalize on Thune’s appeal to grass-roots activists and donors.

The South Dakotan will be the first guest to appear on the Republican National Committee’s new Internet-based television program “Off the Record,” which is scheduled to be e-mailed today to 7.5 million Republicans. The Senator will speak about his recent trip to Iraq, among other topics, in the interview-format show designed to provide viewers “candid interviews with party leaders, activists, and rising stars in the GOP.”

And late last month, Thune was named chairman of the Inner Circle, a fundraising program run by the National Republican Senatorial Committee geared toward low-dollar donors.

“He is a giant-killer,” said Mark Rodgers, staff director of the Senate Republican Conference. “Anyone who takes down a sitting leader is a celebrity in their own right. He has risen above the crowd.”

In addition to Obama and Thune, freshman Sens. Mel Martinez (R-Fla.) and Ken Salazar (D-Colo.) — the only two Hispanic lawmakers in the chamber — are also in demand. This past weekend, Martinez appeared at a fundraiser for Sen. Jon Kyl (R) in Arizona, and Salazar said he is getting flooded with appearance requests.

Salazar said he is processing the requests, but added, “Right now, my priority is to really focus on making sure I get my wheels on the bus as a new U.S. Senator.”

Martinez said he is also reviewing the requests, but added he does not expect to accept many invitations beyond helping Florida Republicans and his new Senate colleagues. In addition to working to retire his campaign debt — $341,000, according to the latest Federal Election Commission filing — Martinez said he wants to focus on his legislative duties.

“I am willing to be helpful” with fundraising, said Martinez. But as for crisscrossing the country to appear at state party fundraisers, the former Housing and Urban Development secretary said that is unlikely to happen.

“I did a lot of that in the Cabinet and I am not going to redo that,” Martinez said. “I went to Saginaw, Michigan, for a Lincoln Day dinner. Don’t be looking for me to do that again.”

Joining Thune as the head of an NRSC fundraising program this year is freshman Sen. David Vitter (La.), whose meteoric rise in Louisiana politics found him moving to the Senate after serving only five years in the House. Vitter is chairing the Presidential Roundtable, a program designed for midlevel donors.

But focusing on their new jobs seems to be a common theme expressed by the freshman Senators. Still, there is a recognition that hitting the fundraising and speaking circuit. is part of their new responsibilities.

“We obviously want to be able to be helpful in every way we can to the team by raising money for candidates and trying to prioritize those who are up this year, and those who are in competitive races,” Thune said.

Already, the South Dakotan has spoken before the National Association of Wholesale-Distributors, International Foodservice Distributors Association and appeared at the Christian Inaugural Eve Gala.

Instead of appearing at fundraisers, Obama said he is helping his colleagues and the Democratic Senatorial Campaign Committee by directly calling donors.

“What I am trying to do is reduce my travel schedule until next year when I anticipate they are going to need me much more,” Obama said. “Right now, mostly what I am doing is I am raising money from people who I know, and asking people to be supportive.”

Obama, the DSCC’s Midwest regional vice chairman, said he is also preparing for a Feb. 23 committee fundraiser that will take place in Chicago.

“Part of my task this year, I think, is just to make sure that my fundraising base that already exists understands how important it is to support other candidates,” the Illinois Senator said.

Still, for all the candidates Obama helps, he is not able to satisfy every Democrat’s request.

“We are trying to get Barack to do some stuff and it is just impossible,” said a Democratic fundraiser, who spoke on the condition of anonymity. “He is the hottest property Democrats have — even hotter than [New York Sen.] Hillary Clinton.”

Even before he was elected, Obama was a fundraising star for the Democratic Party. Obama estimates that he “raised about $1.3 million altogether in various ways for other candidates” in 2004. And he cut a $150,000 check in January to help the DSCC retire its debt.

In the near future, Obama will travel to New Jersey for Lautenberg, help raise money for Sen. Debbie Stabenow (Mich.) in Chicago and attend a non-fundraising event honoring Rep. John Lewis (Ga.) in Georgia.

Several of the freshman Senators are also extending their political reach beyond the traditional fundraising avenues by opening political action committees. Obama, Thune and Sens. Richard Burr (R-N.C.) and Johnny Isakson (R-Ga.) have active PACs, and Salazar indicated last month he is in the process of opening one.