For instance, Southern Co., an Atlanta-based electric utility with 26,000 employees, found that many workers already had made plans to retire in the next five or 10 years but were also interested in coming back to work on a temporary basis. As a result, the company created a "retiree reservists pool" for its Georgia unit, a database of several hundred retired workers who can be called on during hurricanes and other emergencies to train new hires and to staff short-term projects. Southern's human-resources department is trying to expand the concept to other business units.

Lincoln National Corp., a financial-services firm in Philadelphia with 5,500 workers, put together a task force last year to design flexible work arrangements for older employees who want to work part time or take longer vacations. Already, the firm is tapping older managers as mentors for new trainees.

International Business Machines Corp. similarly taps some retirees to work on special projects so they can share their expertise with younger workers.

And the company's 330,000 current employees are being encouraged to post detailed descriptions of their job experience in an online directory called the "Blue Pages" so that employees far from retirement can find "knowledge before it walks out the door," says Eric Lesser, an associate partner in IBM's business-consulting services unit in Cambridge, Mass.

Home Depot Inc. last year launched a partnership with AARP to recruit older workers, many of them laid off from other companies. "We needed more experience, more reliability and people who were great with customers," says Dennis Donovan, executive vice president of human resources at the Atlanta home-improvement retailer.

Home Depot, with more than 325,000 workers, offers health coverage even to part-timers, which was enough to lure Dick Kiefer, 65, who retired from a thrift shop at age 62 but worked the bulk of his career as an appliance salesman for the former Montgomery Ward & Co. in Des Moines, Iowa. Now he qualifies for Medicare but is keeping his Home Depot job — and recently increased his hours to 40 a week from 25.

"There's no stress," he says. Being on his feet all day means "you have to wear thick-soled shoes, but I've never known anything else."