William Vandergrift and Phil Turner have been friends since second grade. Vandergrift calls the day they met while attending elementary school outside Pittsburgh "a terrible day in our lives."

Over the years, Turner has learned to counter the ever-sarcastic Vandergrift with a roll of the eyes and a counter jab. Their banter--the kind rooted in deep affection and trust--sounds a lot like a session with National Public Radio's "car guys," Click and Clack.

Together, Vandergrift, 56, and Turner, 57, run Interlink Systems Group Inc., an 11-person physician practice management software company based in a converted town house in Leesburg's historic district. Although they are considerably older than the army of young techies who have taken the entrepreneurial and high-tech worlds by storm, their two-year-old software company doesn't show it. Most employees hover around age 29; somebody on the staff has brought a guitar to work, somebody else Star Wars posters.

For Turner, small is the only way. He was an entrepreneur before it was cool, he said.

"My last job [working for someone else] was in 1968," he said proudly.

Sitting beside him at the conference table, programmer T.J. Griffin, 28, can't resist a flip remark: "Was that the summer of love?" he asked with a straight face.

"Back in the late '60s, there were a lot of those," Vandergrift said.

When most of his friends were looking for prestigious jobs with big companies, Turner struck out on his own ("I was sort of a rebel, I guess") to start a company that installed large software systems for wholesale food distributors, air freight companies and the like.

During the 1980s, he took the advice of his accountants, who told him the medical industry was in dire need of software to streamline billing. By the end of the '80s, he was focusing solely on the health care field. He developed a software program called MedArs, which he sold under a company of the same name based in Philadelphia.

Interlink is the second incarnation of MedArs. An updated version of the software, which was ready about a month ago, is already being installed in billing centers throughout the country, Turner said. It is programmed with Medicare and managed care rates, automatically calculating the cost of office visits.

Griffin and several tech support workers and programmers are responsible for supporting and making improvements to the software. Eventually, Turner hopes to develop a network of physicians linked through an intranet--a private network--and therefore able to share patient information, disease demographics and billing rates.

Griffin likes to joke that he and most of the other employees "represent the new order" of Interlink. He was the last technical person hired in a group that worked for the Student Loan Marketing Association, and he jumped at the opportunity to leave the corporate setting. He said Interlink's environment helps foster creativity--he also works on marketing issues and helps with the financial operations--and he enjoys learning from older and wiser bosses.

Vandergrift is big on hiring people who not only have technical expertise (he and Turner located the company in Northern Virginia to tap into its high-tech talent pool) but also fit into a company culture noted for its "shoeless weekends"--which sometimes carry over into Monday--and "Beer Thursdays" after work. And he is constantly on the lookout for the good fits. He met Matt Glick, the first programmer Interlink hired, through his daughter.

He also has been known to raid his favorite coffee shop for employees. "We're in the first stages of a takeover of Starbucks," he said, between sips of his daily drip.

He met Amber Amidzich, 23, during his daily visits to the Leesburg Starbucks, where she was the assistant manager. "There was nobody in there who had any personality but Amber," he said. One day he told her what he thought--and eventually offered her a job. She recruited Jacquie Johnson, 29, former manager of the Starbucks in Sterling Town Center.

The family-like atmosphere of Interlink--where both of Turner's sons work and Vandergrift's daughter helps out on the phones before she goes off to college--is carried over into the office next door. There, linked by a shared back porch, Lee Ann Rewey runs Universal Claims Network Inc., a medical billing training center and authorized dealer for Interlink.

Rewey had done consulting work for Turner for several years when he asked her if she would be willing to establish a training center for his software. She agreed, and the two thought it would be a good idea for her to locate close by. She found the town house, and Interlink moved in after growing out of its previous office space on Catoctin Circle.

The arrangement has worked well, she said. "There's a lot of bopping back and forth." She often runs next door to ask questions about the software system or to help the company work through bugs in the product.

Although Rewey has only five employees, two of whom are family members, she said her company's atmosphere is not quite as relaxed as Interlink's. However, she does admit the atmosphere is somewhat "laid-back." And her hiring style, at least, seems right in line with that of her neighbors. She met Geri Lindsay, her number two at Universal Claims, on the golf course.

CAPTION: Leesburg-based Interlink has a close ally in Lee Ann Rewey, whose firm next door provides training in Interlink's medical billing software.

CAPTION: Phil Turner, left, co-founder of Interlink, and his partner, William Vandergrift, are both in their fifties, but they preside over a two-year-old company whose oldest employee is 29--which is exactly what the two longtime friends want for their small firm.