Everyone’s talkin’

Paul McCartney will make his first-ever visit to David Letterman’s “Late Show” Wednesday (11:35 p.m./Ch. 2) to promote his upcom ing tour, which kicks off Friday at Citi Field in Queens. McCartney will chat with Letter man, and will perform later in the show — on the same stage on which he and his Beatles bandmates made their US debut on “The Ed Sullivan Show” in Febru ary 1964.

Wendy Williams, mean while, welcomes Vanessa Williams (“Ugly Betty”) as her first guest on today’s launch of “The Wendy Wil liams Show” (10 a.m./Ch. 5), which aired in select markets last summer and is now rolling out nationally.

And, tonight, the cast of Broadway’s “Hair” will do something extremely rare — perform on a late-night talk show in LA. They visit Conan O’Brien’s “Tonight Show” (11:35/Ch. 4) and had to charter a private plane to make the trip (because of the 50 cast members and the lo gistics); it’s the first time in “Tonight’s” history that a company of this size has ap peared on the show.

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NBC has delayed the start of “Parenthood,” which was supposed to premiere this fall, until midseason, due to the (undisclosed) illness of star Maura Tierney. Shoot ing was set to begin July 27.

It’s the second incident to befall “Parenthood” (based on the 1989 movie); NBC exec Nora O’Brien died on the set last April.

Last, but not least:

* NY1’s Cheryl Wills em cees tonight’s NAACP/NY State Chapter event at the Met . . . MSG’s Jill Martin leading kids from Children’s Aid Society on a tour of the Garden as part of MSG’s “Garden of Dreams” initia tive. . . Mickey Burns inter viewed funnyman Pat Coo per at Sugar Bar (W. 72nd) for “NYC TV Profiles,” which recently won a Telly Award.