When Chicago high schools close for the summer later this month, Illinois Bell Telephone Company will begin teaching 100 economically disadvantaged teen-agers how to operate computerized word processing equipment. The students will be paid $3.35 an hour during the training period, benefiting from an increasing corporate desire to use summer jobs for training and career-building.
''They will go back to school as seniors having acquired a highly marketable skill,'' says Peter Henderson, executive director of Chicago United, a group of business leaders which hopes to find 5,000 summer jobs for needy youths.
Meanwhile, Gulf Oil Corporation is giving grants of $50,000 to five cities. Local groups are using the funds to cover the cost of lining up jobs for youths and to hire teen-agers to work for local charities.
''We are trying to give (students) the opportunity to make some money for the first time in their lives and give them a look at the economic system,'' says Gulf spokesman Barry Smyth.
As the academic year winds up, an estimated 3 million teen-agers will be looking for summer jobs. While companies in many communities are still hurt by the recession, enough are increasing summer hiring to boost significantly the number of available summer jobs.
''We estimate there will be a 30 to 40 percent increase in private-sector summer jobs,'' says William H. Kolberg, president of the National Alliance of Business, which works on increasing private-sector training and jobs for disadvantaged youths. Last year business groups lined up 275,000 jobs for teen-agers, the US Labor Department estimates.
Companies are stepping up summer hiring for a variety of reasons, including a pickup in business and a new tax break. This year they will get a tax credit of 85 percent of the salary they pay to economically disadvantaged summer workers under age 18. So if an employer pays the minimum wage of $3.35 an hour, the after-tax cost is only 50 cents an hour.
''A lot of companies, particularly large ones like AT&T, Sears, Roebuck, J. C. Penney, and McDonald's, are excited about it,'' Mr. Kolberg says. And the Labor Department expects the tax law provision, which was included in the Tax Equity and Fiscal Responsibility Act of 1982, to produce between 60,000 and 100, 000 jobs this summer.
The jobs are typically entry-level positions in mailrooms, clerical operations, or the company cafeteria. A small but growing number of companies, however, are trying to offer summer jobs with some growth potential or provide training that will help teen-agers land such jobs in the future.
''Jobs for (high school) seniors have to have a career ladder; they can't be dead end,'' says Ted Dooley, director of youth programs at the Boston Private Industry Council, a group of executives which lines up summer jobs for inner city youth. For example, a summer worker at one of the Boston banks might start by entering data into a computer with the understanding he could work up to a teller's position.
And in Houston, an oil service company will teach summer workers job hunting skills, including ''how to prepare a resume and how to dress on a budget,'' says Julia Steinman, of the Greater Houston Alliance of Business youth program.
''There is a sincere and growing interest among corporations in participating with public agencies in delivering (job related) training,'' says Andrew B. Hahn , director of the Center for Employment and Income Studies at Brandeis University.
One reason for the growing corporate interest in training is that on Oct. 1 the Job Partnership Training Act goes into effect. The law, which replaces the controversial Comprehensive Employment and Training Act (CETA), mandates the formation of private industry councils in major population centers. The councils will have veto power over local government job training and placement programs funded by the federal government.
So next year business will have a much bigger say in designing and delivering federally funded summer jobs, which significantly outnumber the summer positions that companies fund.
This year, for example, Congress has appropriated funds for some 813,000 public-service jobs, vs. 683,000 last year. The government's own personnel office will hire an additional 35,000 to work in federal offices, about the same number as last year.
Despite increased hiring by the government and the private sector, most experts say there will still be far from enough summer jobs to go around. As a result, the teen-age unemployment rate, which dropped 0.4 percent in May, could climb. By contrast, the nation's overall unemployment rate in May was 10.1 percent, down 0.1 percent from April.
And the official youth jobless rate ''is pretty understated; the problem is much more severe'' than the numbers show, says Nathan Weber, a research associate at the Conference Board, a business research organization that recently completed a study of the summer job situation.
Embedded in the teen-age jobless rate is a black teen-age toll of 48.2 percent. And even that figure understates the problem, since only 36.4 percent of black youths participate in the labor force by working or looking for work. A person is not counted as unemployed unless he is seeking work. The Labor Department expects labor force participation by both black and white teen-agers to fall this summer.