Bethlehem Mayor John Callahan (D) has made it official: He announced Monday that he will challenge Rep. Charlie Dent (R) in 2010.

“I’ll be an independent voice for our district that’s focused on finding bipartisan solutions to address the many challenges we’re facing,— Callahan said.

Dent has easily won re-election in the competitive eastern Pennsylvania district since his first campaign in 2004 because, Democrats say, he has never had a serious challenger. Democrats are confident that Dent will have a much tougher time with Callahan as their nominee.