NBC News President Neal Shapiro finally told his staff in a memo that he would leave the job Friday, ending months of chatter that he was stepping/being pushed aside.

NBC Universal President Jeff Zucker said in his own memo to staffers that Steve Capus would serve as acting president of NBC News. Capus was elevated from "Nightly News" executive producer to senior VP at NBC News in June.

"Since last spring, there's been a lot of speculation in the press about my tenure here. I've made a decision and I wanted you to hear about what's happening from me," Shapiro said in the opening line of his memo, sounding almost as if he weren't a member of that same "press," but a suit at, say, FEMA.

According to that speculation in the press, Shapiro has been negotiating his exit for months. Since about May, actually -- the same month "Today" show Executive Producer Tom Touchet got the hook, after the NBC News cash cow slipped in the ratings to numbers perilously close to those of ABC News' "Good Morning America."

But, according to Shapiro's memo, it all started for him way back when they began their annual planning this year and he began to think about his future at NBC.

Specifically, the 12-year network veteran said, he wondered if the next few years would be as personally fulfilling as the first four he has spent as the president of NBC News. He found himself missing the opportunity for the kind of creativity he'd had in previous jobs, he said.

(Shapiro had been recruited from ABC News in '93 to executive-produce "Dateline," which had just disgraced itself by rigging a fire in a crash test of a General Motors truck. Under Shapiro, "Dateline" recovered and prospered; he was named head of the news operation in 2001.)

"Reflecting on all of this, I've concluded that it's time to move on to a new challenge," Shapiro said in the memo, a copy of which was obtained by The TV Column, along with Zucker's memo.

Neither guy was available to talk, an NBC News rep said yesterday.

Shapiro's tenure helming the news division has had its ups and downs.

On the plus side, he oversaw the handoff of the nightly news anchor job from Tom Brokaw to Brian Williams, which pretty much everyone concedes went extremely smoothly and looked like pure genius compared with what's been going on over at the CBS evening newscast.

In the minus column, there's that "Today" slide, though the numbers have been getting better since the dark days last spring when, one week, only 40,000 viewers separated "Today" from "GMA." (Last week, the gap was about 600,000 viewers, according to early estimates.)

And MSNBC continues to trail its cable news competition badly; last week, its total-day average was 766,000 viewers, compared with CNN's 2.1 million and Fox News Channel's 2.8 million (though that did represent a 250 percent increase compared with MSNBC's year-to-date total-day average.)

Shapiro, who is leaving in the middle of one of the biggest news stories of the year, did not say what his plans are. Zucker, in his memo, said it gave him "great confidence" to know that Capus will assume the post for the time being, calling his experience over the past two decades within NBC News "virtually unparalleled." Capus's resume includes gigs at the NBC affiliate station system, at NBC News Channel, "NBC News at Sunrise," "Today," MSNBC and "NBC Nightly News."

"I've concluded that it's time to move on to a new challenge," NBC News President Neal Shapiro said in the memo.