The A-yip-i-o-ee-ay Postal Station, State College, Pa., is open for business and the philatels are going to take notice.

The musical Oklahoma! is 50 years old, and the Center for the Performing Arts (CPA) and the State College post office are teaming up for a little cross-promotion of the show's commemorative stamp.

A special hand cancellation of the stamp will be distributed to audience members at Saturday's performance.

State College Postmaster Paul Mackes said special cancellations are often used to promote an event while attracting attention for the stamp and the U.S. Postal Service. He expects that philatels, or stamp collectors, will scramble to create a collectible by sending their Oklahoma! stamps to be cancelled at the A-yip-i-o-ee-ay Station.

"They always do," he said, adding that there will be a notice of the special cancellation in all the philatelic magazines. (The station's name comes from a suitably corny phrase from Oklahoma's! title song.)

The postal regulations are detailed for this little two-sided promotional maneuver. Whenever a special promotion like this one is planned, there must be a makeshift postal station set up nearby, even though the stamps are precancelled. As an added bonus, University Park's Clown Prince of Postage -- Mike the Mailman -- will man the temporary station in the lobby of Eisenhower Auditorium.

In order to follow the specific standards for the cancellation hand stamp, CPA staffers conferred with contacts at the State College headquarters of the American Philatelic Society.

Carolyn Rinaldi-Lieb, CPA publicity coordinator, was pleased that the U.S. Postal Service donated about $800 worth of stamps for the cancellation -- and amused at the highly regulated steps they had to take to fulfill the requirements of the cancellation.

But Mackes takes the whole process very seriously.

"Stamps are little pieces of art," he said. "They do well for the post office . . . a stamp is a promise of a service, so we need to protect it through the financial audit system. It is as good as money."