Leno's last `Tonight' is May 29; O'Brien in June 1

Kimmel, identifying himself as a Florida newspaper reporter, tweaked his bosses as he posed questions about his job security if Leno comes to ABC; Leno, on the other hand, represents a threat to NBC if he goes elsewhere.

"(Green Bay Packers quarterback) Brett Favre retired and then wanted to come back," Leno said to Silverman and Graboff. "The Packers said no. What do you make of that?"

Favre retired in early March but recently expressed second thoughts about playing in 2008. The change of heart has drawn lukewarm enthusiasm from the Packers, who spent the offseason planning to move ahead with Aaron Rodgers as their starter--akin to the O'Brien-Leno switch.

"Everyone's entitled to change their mind. But I'd imagine that puts management in an impossible situation," Silverman replied, gamely.

"Is it true you've offered Leno a fifth hour on the `Today' show?" Leno said.

"That's a great idea, actually," Silverman said.

Nah, replied Leno, "It's a crappy idea."

Jimmy Fallon is poised to take over O'Brien's "Late Night" in March or April of 2009, after honing his approach in brief Internet shows, Silverman and Graboff said.

O'Brien will wrap his "Late Night" run sometime in the first quarter of the year, with exact dates to be determined, the executives said. O'Brien reruns will fill the gap until Fallon takes over.

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