WRAPUP 8-Palin defends experience, slaps Obama

* Palin works on big speech to convention

* McCain defends Palin against critics

* McCain arrives in Minnesota, greets Palin

By John Whitesides, Political Correspondent

ST. PAUL, Sept 3 (Reuters) - Sarah Palin defended her qualifications for U.S. vice president in a highly anticipated speech to the Republican convention on Wednesday, saying her job involved actual responsibilities -- unlike Barack Obama's.

Since John McCain made the virtually unknown Palin his choice for vice president, the Alaska governor has been the center of a media storm fueled by disclosures about her unmarried teenage daughter's pregnancy, a probe into her role in an Alaskan official's firing and questions about her political record.

In her debut in the public spotlight, the former mayor of Wasilla, Alaska, contrasted her experience with Obama's work as a community organizer in Chicago.

"Before I became governor of the great state of Alaska, I was mayor of my hometown. And since our opponents in this presidential election seem to look down on that experience, let me explain to them what the job involves," Palin said in remarks prepared for delivery on Wednesday.

"I guess a small-town mayor is sort of like a 'community organizer,' except that you have actual responsibilities," she said.

Palin's anti-abortion and pro-gun history has excited conservatives and party activists but the appearance on Wednesday will be the first chance for voters nationwide to judge for themselves.

It comes just five days after McCain shocked the U.S. political world by introducing the 44-year-old first-term governor as his running mate at an Ohio rally.

"Americans are going to be very, very, very pleased. This is a very dynamic person," McCain said of Palin in an interview with ABC News.

"She is experienced. She's talented. She knows how to lead and she has been vetted by the people of the state of Alaska. But most importantly, people in America want change. They don't want somebody from inside the Beltway," he said of the ring road around Washington, D.C.

The Republican McCain, 72, an Arizona senator, and Palin will face Democrat Obama, 47, and his vice presidential running mate, Delaware Sen. Joe Biden, 65, in the Nov. 4 presidential election.

The McCain campaign released a television ad comparing Palin's experience with the qualifications of Obama, a first-term senator from Illinois. "She's earned a reputation as a reformer," the ad's narrator says. "His reputation? Empty words." (Editing by Howard Goller and Patricia Zengerle)