Holding forth at the Hyatt: Talking up a storm, talking turkey, talking blues, talking issues, talking bull at the International Platform Association's 155th annual convention.

Talking tasteless, if you ask White House chief of staff Donald Regan. Orating after hairdresser Robin ("Washington Under the Dryer") Weir and the woman who played "The Happy Wanderer" on water-filled Coke bottles, Regan was confronted yesterday by Rep. Mary Rose Oakar (D-Ohio), who had more than kudos on her mind.

With media-planned cheekiness, she presented him with a twinkly pin and said, "I want to give you a fake diamond, because that's what most American women wear."

"That was a misquotation," said the beleaguered chief of staff, referring to his comment -- "Are the women of America prepared to give up their jewelry in favor of sanctions against South Africa?" Regan was clearly not happy about the ambush.

"You're just trying to take political advantage of it," he said, manfully holding his ire in check. He had just spent 20 minutes extolling the Reagan administration after receiving the IPA Theodore Roosevelt Award for public service.

"We can't afford diamonds under your policies," said Oakar.

Regan left. He kept the diamond.

Later, a spokesman said Regan was "neither furious nor angry," at the incident, just "disappointed."

"I liked that pin," said Oakar, after she lectured on "the future of the Democratic Party." "I paid $3.50 for it at a flea market in Ohio."

The annual IPA meeting, explained an association press official, is "serious . . . and, at the same time, a little circuslike."

Indeed, it seems something of an updated Buffalo Bill's Wild West Show. But instead of Annie Oakley shooting 'em up, you get G. Gordon Liddy talking about his book "Surviving or Prevailing." You get Harry Blackstone Jr., and the Penn & Teller duo performing magic. Heloise will chat about how "Laughter is the Best Medicine." Art Linkletter, Pearl Bailey and Loretta Lynn will join Dr. Henry Heimlich, who will speak on "Maneuvering for a Better Life." And Sen. Warren Rudman (or is it Gramm?) will continue to insist the country can be run by computer.

All for what? The chance for IPA conventioneers -- booking agents every one -- to see what the speakers can do at the lectern. After this, presumably lecture bookings will follow in the town halls of Schenectady and beyond at negotiable prices.

Very negotiable. "I don't talk for less than $1,500," says Robin Weir, who has fondled the hair of Nancy Reagan, Indira Gandhi and Joan Rivers.

If you want Diane Sawyer (for a lecture), says lecture agent Judith Geller, it'll cost you $22,000. Yup. And Dinah Shore is available for $25,000. Zsa Zsa Gabor's a thrifty $8,000 to 10,000 and radio guest-baiter Larry King is a steal at $6,000.

The lecture, naive waffler, is no longer the domain of neo-Daniel Websters. It is the verbal activity for which your Elks convention is to be charged.

"What we've gone into," says IPA Director General Dan Tyler Moore, "is the golden age of the lecture business in all history. It's a golden era just like the ones of Greece and Rome. It's become the highest paid profession per hour in the U.S. Kissinger gets anywhere from $18,000 to $22,000 for a one-hour speech, plus expenses. Bob Hope will charge $40,000 for a speech."

Some romantic lecturers (they just want to be heard) compete in something called "The Speakers' Ladder," a sort of annual IPA lecture playoff. You may talk, they are told, on what you will. Thus: "It is time for mediocrity to be treated as a subject for study," says speaker Al Michaud, a competitor. "There is an alternative" to American military escalation in Nicaragua, declares a concerned Lawrence Tracy, who then gives none. "Damn you, damn all of you," begins Dee Wright, who is standing next to a trash can that was dressed up like a young girl.

Wilma Cummins, the former school teacher, plays her theme on eight Coke bottles. "I've had some requests," she says, "but I'm going to play anyway."

Start light, act self-deprecating, go for anecdotes, strategizes Letitia Baldrige, self-appointed etiquette adviser to the upward-but-wayward. "I'm queen of the great gaffes," she says, and tells of her boo-boos when she introduced a Pakistani ambassador as being from India and seated a top French official next to his wife's lover. She saw the light, however, and wrote "Letitia Baldrige's Complete Guide to Executive Manners," soon to be a major series of lectures.

Magicians Penn & Teller's version of keeping it light shows less restraint. Penn Jillette asks an audience member to inspect a large pin to be used in a magic trick. "Feel it or I'll stick it through your goddam neck."

There are doctors who tell you that you will soon die of cancer. Some U.S. News & World Report editors discuss "the year ahead." Tomorrow, Tom Brokaw will receive the Lowell Thomas Award. And there's more.

But you don't want to know.