UPDATED: Democratic primaries: In NY, Rep. Maloney will challenge Sen. Gillibrand. In PA, Rep. Sestak will challenge Sen. Specter.

UDPATE @ 4:31 PM via Greg Sargentwe learn that it's not "official" yet for Sestak:

But Sestak spokesperson Jonathon Dworkin tells me that in fact, Sestak has not made a final decision. Dworkin says Sestak told the paper what he’s been saying to everyone else: He’s still talking to his family about whether to run.

“He mentioned his daughter in the interview,” Dworkin said. “He hasn’t made a final decision. He’s still on the same timeline as before. That has not changed.”

Dworkin confirmed, however, that Sestak had set forth on a tour of all of Pennsylvania’s counties. But is he in the race yet?

Nope. Sorry.

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Two of the newest Democratic Senators, New York's Kirsten Gillibrand, who was appointed by Governor Paterson to take Hillary Clinton's vacant seat, and Pennsylvania's Arlen Specter, who switched parties, will be facing primary challengers.

Via The Hill:

An adviser to Rep. Carolyn Maloney (D-N.Y.) confirmed Wednesday that the congresswoman will enter the state’s Senate primary against appointed Sen. Kirsten Gillibrand (D-N.Y.).

Paul Blank, who works with Democratic consultant Joe Trippi’s firm, said Maloney is officially in the race. Blank is set to serve as a top adviser for her Senate campaign.

"Congresswoman Maloney has made her decision,” Blank said. “She believes times are too tough and our challenges too important for politics as usual.

He added: “Congresswoman Maloney is putting together a campaign team and will make her announcement in two weeks."

And, The Hill again:

Rep. Joe Sestak (Pa.) said Wednesday he will challenge Sen. Arlen Specter (Pa.), becoming the second House Democrat in the past few hours seeking to unseat an incumbent Senate Democrat.

“I am going to get into the race against Arlen Specter in the Democratic race for senator,” Sestak told the Wayne Independent on Wednesday morning.

This is good for the process. Senate seats aren't inherited or bestowed upon people, although many in the Senate seem to think that's the case. Also, opportunities to run for the Senate don't happen very often.