Those of you who caught me on The O'Reilly Factor last night might be wondering that very question, as it became the sticking point between the Big O and yours truly. Here's the discussion of the matter from the widely hailed and authoritative site Snopes.com:
The most serious accusations..., that Fonda turned over slips of paper furtively given her by American POWs to the North Vietnamese and that several POWs were beaten to death as a result, are untrue. Those named in the inflammatory e-mail categorically deny the events they supposedly were part of.
"It's a figment of somebody's imagination," says Ret. Col. Larry Carrigan, one of the servicemen mentioned in the 'slips of paper' incident. Carrigan was shot down over North Vietnam in 1967 and did spend time in a POW camp. He has no idea why the story was attributed to him, saying, "I never met Jane Fonda."
The tale about a defiant serviceman who spit at Jane Fonda and is severely beaten as a result is often attributed to Air Force pilot Jerry Driscoll. He has repeatedly stated on the record that it did not originate with him.
Mike McGrath, President of NAM-POWs, also stepped forward to disclaim the story:
Please excuse the generic response, but I have been swamped with so many e-mails on the subject of the Jane Fonda article (Carrigan, Driscoll, strips of paper, torture and deaths of POWs, etc.) that I have to resort to this pre-scripted rebuttal. The truth is that most of this never happened. This is a hoax story placed on the internet by unknown Fonda haters. No one knows who initiated the story. Please assist by not propagating the story. Fonda did enough bad things to assure her a correct place in the garbage dumps of history. We don't want to be party to false stories, which could be used as an excuse that her real actions didn't really happen either. I have spoken with all the parties named: Carrigan, Driscoll, et al. They all state that this particular internet story is a hoax and they wish to disassociate their names from the false story.
The whole Snopes account, which is extremely critical of Fonda's actions during the Vietnam War, is here.
Urban Legend's take on the same matter here. This also concludes that Fonda did not hand over messages from US POWs.
Both the Snopes and Urban Legend versions confirm that a prisoner, Michael Benge, was beaten by Vietnamese captors for refusing to meet with Fonda.
My review of Fonda's autobio is here.
[A shout out to H&R commenter Sage, who threw in most of the above in the discussion below of Hanoi Jane, Bill O, & Me.]