At least once a week, usually more, a caller or letter-writer will get in touch with us and ask the question:

''Whatever happened to the kid with the pennies?''

That`s always the phrase: ''the kid with the pennies.'' It seldom varies.

Well . . . the kid with the pennies graduated from college Sunday. Which takes us back to where we all came in on this thing.

In 1987, a young man named Mike Hayes contacted me with an intriguing idea. Hayes, 18, of Rochelle, Ill., was about to enroll at the University of Illinois. He wasn`t an impoverished fellow, but he didn`t know where his college money was going to come from. He didn`t want to borrow from his parents, because they would have to go into debt to help him.

So he came up with an idea:

What if I asked the readers of my column to send him a penny? Just a penny from any reader who was willing to do it.

''A penny doesn`t mean anything to anyone,'' he said. ''A penny just doesn`t count.''

I asked him how many pennies he needed.

''Well, we`re talking about four years of college,'' he said. ''Tuition, room, board, books. . . .''

''How many?'' I said.

''I figure 2.8 million pennies ought to do it,'' he said.

2.8 million pennies is the equivalent of $28,000. $28,000 is a lot of money, but a penny isn`t.

So I wrote about Mike Hayes in a column. He rented a post office box

(under the name ''Many Pennies for Mike'') in Rochelle, which is in the middle of farm country and has a population of 9,000.

He got his college money-all 2.8 million pennies, or at least the equivalent of that. Some people sent nickels. The pennies came from all 50 states, from many European nations, from Mexico, Canada, the Bahamas and Japan. He went off to college-on a full ride from the penny-senders.

So whatever happened to the kid with the pennies?

''My degree from the U. of I. is in food science,'' Mike Hayes said the other day. ''It`s been a great four years in college, but now it`s time to graduate and go out and get a job.''

At first, he said, he was a celebrity on campus-because of the publicity that came to him as the result of the penny stunt, he was famous for a while. Television stations interviewed him, young women from around the country sent him their pictures (apparently because they admired his entrepreneurial spirit), strangers stopped him to ask him questions, a former Miss America even wrote him a friendly letter.

Lately, though, he has been fairly anonymous. On a college campus, four years is a lifetime. Mike Hayes, as a senior, became just another old-timer at the U. of I.

''My friends still know,'' he said the other day. ''I don`t hear so much from strangers anymore. But my friends call me `Penny Man.` That`s their nickname for me.''

He knows that there must be a certain amount of resentment toward him. After all, he didn`t do anything to earn those 2.8 million pennies. He wasn`t a hard-luck case. He hadn`t had an unfortunate upbringing. He was just a kid from the middle of the country who had a clever idea. It ended up putting him through four years of college.

''I know this whole thing was sort of funny,'' Hayes said the other day.

''But as I graduate, I just want to thank everyone who sent a penny. The idea made people laugh, but I`m not sure I would have made it all the way through college if this hadn`t happened. So I`m glad that the penny thing caused people to smile-but I`m more glad that I got to go to college.''

There`s one more thing:

Mike Hayes needed the 2.8 million pennies to pay for college, but he ended up getting approximately 2.9 million pennies. So there`s an extra $1,000 in the Many Pennies for Mike account.

He and his family saved a lot of the letters that arrived in Rochelle four years ago. ''We have about 90,000 of the letters stored in my brother`s basement,'' he said.

Mike plans to give the extra $1,000 to a deserving college student from one of the families that sent him pennies. ''I`m not going to be real scientific about it,'' he said. ''I`m just going to stick my hand into those 90,000 letters we saved, start calling people whose names are on the envelopes I grab, and ask if there`s a person in their family who needs $1,000 for college. I`m going to trust them-I`m going to count on them to tell me if they don`t really need the college money. If they don`t need it, I`ll move on to the next envelope.''

Sort of the Many Pennies for Mike Scholarship.

''This whole thing has been very goofy,'' he said. ''Tell everyone how much I appreciate it.''