Craig Kilborn is bowing out as host of CBS's post-"David Letterman" late-night show.

Kilborn failed to reach a deal for a new contract after weeks of talks, sources say, and he and the network were far apart on salary.

A CBS rep would not discuss the particulars. "We'd been talking to him about a new deal since as early as May, but throughout the summer," the spokesman told The TV Column.

On Thursday, "Craig just came to us and said that he didn't want to do it anymore, he wanted to do something different," the rep said.

Kilborn then got out ahead of the story by telling trade paper Variety late Thursday that he had decided to call it a day so he could have time to "focus on writing and producing different television projects I haven't had time for."

Kilborn's last day as host of "The Late Late Show" could come as early as the end of this month. The show was already scheduled to be on hiatus the first two weeks in September. The CBS rep said the search for a replacement began immediately.

The rep stressed that CBS was happy with Kilborn's performance in the time slot that had been occupied by Tom Snyder from January '95 until shortly before Kilborn debuted in March '99:

"Craig did a really good job for us in that time period. . . . Ratings and revenues did increase pretty substantially, both total viewers and demographics. He did what we asked in the time period, brought us younger viewers and helped us make more money in the time period."

Hmm. Let's take a look:

During his run, Snyder averaged 1.6 million viewers and a 0.7 rating among 18-to-49-year-olds; the median age of his audience was 421/2 years.

In his tenure, Kilborn's show has averaged 1.5 million viewers and a 0.7 among 18-to-49-year-olds; the median age of his audience is 411/2 years, according to Nielsen. This season Kilborn's show has averaged 1.7 million viewers and a 0.7 rating in the demographic group.

Meanwhile, his time-slot competitor, NBC's Conan O'Brien, is averaging nearly 2.6 million viewers -- granted, with a larger lead-in audience provided by Jay Leno than Letterman serves up to Kilborn.

Kilborn retains about 39 percent of his Letterman lead-in; O'Brien about 43 percent of Leno's lead-in. In the 18-49 demographic, which is the target audience for these late-night shows, O'Brien hangs on to about 55 percent of Leno's audience and Kilborn about 46 percent of Letterman's.

Kilborn was all the rage back when he was a co-anchor of ESPN's "SportsCenter." Then he went to Comedy Central's "The Daily Show," where he was considered so hot Esquire did a feature on him. Kilborn said in the course of that interview that if he ever wanted his female executive producer to do to him what Dick Cheney this summer suggested Sen. Patrick Leahy should do to himself, she would.

Kilborn thought to add, "There are a lot of bitches on the staff and hey, they're emotional people."

Is it any wonder that when CBS was looking for someone to replace Snyder and, hopefully, attract more young male viewers, they went with Kilborn instead of Jon Stewart, on whom they had an option?

But these days, Kilborn is yesterday's news, while his rival O'Brien is the rage. Reportedly Fox and ABC are eyeing O'Brien, who has been itching to get an earlier time slot and very publicly expressed his displeasure that NBC recently signed Leno to "The Tonight Show" through the end of the decade. O'Brien will be available in December. Sources in Hollywood say it would be incredible for CBS to get O'Brien to even entertain the idea of taking Kilborn's slot without a guarantee that Letterman will retire -- soon.

The "Late Late Show" audience has grown a bit since Kilborn became host.