"He's inundated with invitations and requests from candidates at all levels of the ballot as well as state and local party committees," a McCain political adviser, John Weaver, said Wednesday.
The committee will help pay for McCain's travel when he gives speeches and allow him to contribute to candidates and party committees.
Weaver said McCain's committee was reactivated in mid-July.
McCain, who ran for president in 2000, fares well in early presidential polling among Republican voters. He dismisses questions about 2008, saying he will wait until after the 2006 election to decide about his political future.
McCain was re-elected to a six-year Senate term in 2004.
McCain originally started the PAC (search) — named after his 2000 campaign bus, the Straight Talk Express — soon after suspending his presidential campaign in March 2000.
He wanted his causes to remain in public view and his political options open. The senator closed the committee in the spring of 2003, ahead of his re-election.
Other potential White House candidates for 2008 either have political action committees or are forming them.