He's still two years away from replacing Jay Leno on "The Tonight Show," but already Conan O'Brien seems to be sizing things up.

"Have you planned any changes while ... you were looking?" Leno asked when O'Brien dropped by the late-night talk show Friday.

O'Brien reassured Leno, the show's host since 1992, that he won't be moving onto its Burbank set any time soon.

"It's years away," O'Brien quipped, adding that rather than succeed Leno in 2009 as planned, he's decided to take the job Rosie O'Donnell is leaving on daytime television's "The View."

"I got the call this morning from Barbara Walters," he said, adding he planned to pick up where O'Donnell leaves off and begin picking on Donald Trump.

Leno joked that the redheaded O'Brien has "got the hair" for the part, although "it's going the wrong way" to really match Trump's elaborate comb-over.

"Exactly," said O'Brien, who has hosted "Late Night" since 1993. (Associated Press)

'Studio 60' back this month

NBC has set a return date for "Studio 60 on the Sunset Strip."

The Aaron Sorkin drama, which arrived last fall as the season's most hyped show and vanished from NBC's schedule amidst sinking ratings, will move to Thursday nights at 10 p.m. starting on May 24.

Not-so-coincidentally, that Thursday is the day after the end of the crucial May sweeps period and it comes a week after the upfront presentation at which NBC will reveal to advertisers whether "Studio 60" has a future on the network next season.

The show's chances for renewal are believed to be relatively slim.

Savvy viewers will recall that this is a return of sorts for "Studio 60." Last May, NBC announced that the series would air on Thursday nights at 9, only to run scurrying to Mondays after ABC moved "Grey's Anatomy" into the same time period.

"Studio 60" had a solid premiere, but by the time February rolled around the series was drawing only around 7 million same-day viewers (factoring in DVR usage gave the series a boost). The last original "Studio 60" aired back on Feb. 19, before NBC shelved it a week earlier than expected for "The Black Donnellys," which failed. (Zap2it.com)

Ad time constant

According to the media agency MindShare, the amount of non-program time on the broadcast networks stayed about the same from 2005 to 2006.

That doesn't mean that the total isn't still big. The networks all spend about 15 minutes an hour on commercials, promos and the like during prime time, but only two networks, ABC and NBC, increased their totals in 2006, and not by much.

ABC had the most non-program time per hour, at 15:38, 12 seconds more than in 2005. Next came NBC, with 14:58 non-program time, then Fox (14:40) and CBS (13:51).

For the record, when you add in the show openings and closings, network hour dramas have fewer than 44 minutes of actual show time, and comedies get fewer than 22 minutes. On the plus side, if you record shows and skip the ads, look how much time you can save.

Cable nets were a bit higher, and MTV had the most non-programming minutes with 16:09, followed by USA (15:48), Lifetime (15:47) and Discovery (15:40).

The biggest reason there wasn't much of an increase among the big broadcasters seems connected to a general flatness in the TV advertising market, but you'd like to think it also had something to do with network programmers realizing that, at some point, too many commercials will chase viewers away. But, probably, it's that first thing. (Rick Kushman, McClatchy Newspapers)

Channel surfing

Disney Channel's "High School Musical 2" will premiere at 8 p.m. Aug. 17. ... University of Pittsburgh professor Lee Gutkind will be a guest on Comedy Central's "The Daily Show with Jon Stewart" Monday at 11 p.m. to discuss his new book about robots, "Almost Human." ... Brian Kaminski of Trafford will compete on "Who Wants to be a Millionaire" (1 p.m., WPXI) Friday and Monday. ... WQED's Chris Moore documentary "In Country" will air nationally on PBS stations, most likely in November. ... In its On Demand "Your Town" folder, Comcast has made available video from the African American Chamber of Commerce of Western Pennsylvania's Candidates Forum held last month. (Rob Owen, Post-Gazette TV editor)