Scott Oki calls the nine years he worked for Microsoft his "dog years". The work is so hard that each year should be multiplied by seven, he explains.

But at 42, Mr Oki was able to retire comfortably in Seattle as a multimillionaire from his job as a senior vice-president of sales marketing thanks to the stock option scheme that Microsoft founder, Bill Gates, had introduced.

Mr Oki had plans to play lots of golf, but now he is building a golf course when he's not running a charitable foundation and donating millions of dollars to children's causes.

Scott Oki is one of a growing number of computer whiz-kids leaving Microsoft in their 30s and 40s rich beyond their dreams and looking for ways to spend their money to help the less fortunate.

Bill Gates whose estimated wealth is $40 billion has not reached this stage yet while saying that he intends to give away 90 per cent of his fortune before he dies. Mr Gates is still building his futuristic $100 million home in Seattle on the steep shore of Lake Washington a few miles from the Microsoft campus.

He has given $200 million for his scheme to connect libraries around the US to the Internet. This represents a half of 1 per cent of his wealth and there are critics who say he is being too stingy so far with his fortune which is almost the size of Ireland's gross national product. But much of Mr Gates's wealth is paper in the form of his Microsoft stock.

Paul Allen (44), co-founder of Microsoft, is worth about $13 billion making him the third richest person in the US. Mr Allen who was once stricken with Hodgkin's disease left the company he built up with Mr Gates and has since given away $135 million to charitable and community organisations in the Pacific North-West. Mr Allen dispenses his wealth through foundations which channel funds to the arts, medical research, forest protection and his Experience Music Project, a $60 million museum which when built in 1999 will look like a smashed guitar.

The project was originally meant to be a shrine to Jimi Hendrix who comes from Seattle but has now grown to be "an interactive music museum celebrating creativity and innovation as expressed through American popular music and exemplified by rock `n' roll".

Mr Allen has also bought the Seahawks professional football team for $200 million to keep it in Seattle, but first he financed a referendum to get public money for a new stadium costing twice that amount.

At a more modest level, there are numerous Microsoft millionaires distributing some of their money to good causes and transforming traditional methods of philanthropy, they like to think. Microsoft Alumnet set up two years ago now has about 1,100 members who are being advised on how to to donate. Microsoft also matches up to $12,000 any donations to charity by its employees.

Paul Brainerd is not a Microsoft alumnus but made his fortune by inventing PageMaker, the software which made desktop publishing possible. He sold his company in 1994 for $450 million and put one-third into a foundation bearing his name which helps protect the environment of the Pacific North-West.

But he kept being asked by young Microsoft millionaires for advice on how to give away some of their wealth. So last June he brought together about 130 potential contributors and set up Social Venture Partners.

SVP is now advertising for applications for projects dealing with children and education in which it will invest venture capital. Mr Brainerd says: "We're trying to nurture and bring along a new generation of philanthropists who might not have gotten engaged until later in their lives."

SVP says that the success of technology firms in the Seattle area "has given rise to a new kind of philanthropist the social entrepreneur. These people are typically business professionals who have achieved financial success at an early age and who are now ready to return their good fortune by giving time, talent and money back to the community".

Others have gone their own way after departing Microsoft. One of these is Trish Millines who works full-time helping children to become familiar with computer technology.

She came from a poor African-American family in New Jersey where her mother cleaned floors and there was no father. Her basketball skills got her a scholarship to university where she got a degree in computer science.

Eventually she came to Seattle to work for Microsoft but left in 1996 after nine years with enough money "not to have to work again". She was 39.

Sitting in the small office of her Technology Access Foundation she explained that her motivation "came from my experience as a woman of colour in the computer industry it can be very tough as there are very few of us and you can get isolated. Then I decided I would try and help the next generation be more prepared for technology".

She and a former mental health employee have set up a course called "Technical Teens" which has just started teaching the basics of computer technology to 31 African-American and Hispanic children from low-income families. They come after school for the 100-hour course after which they will be placed in companies as interns. When they complete the course they will get a $1,000 scholarship towards higher education.

Tina Podlodowski, the daughter of Polish immigrants, left Microsoft five years ago at 32. "I was working 14-hour days, seven days a week one of the reasons I left Microsoft was to have a life".

Another reason was to be "more active and visible" as a lesbian in the community. She has set up a fund for Gay and Lesbian Families with Children and she has also been elected to the Seattle City Council where her skills have helped save the city millions in computer costs. "Ask me for my brains first and then ask me for my money," is her motto. "Nobody wants to be a passive donor."

Ida Cole had not meant to get into philanthropy when she left Microsoft at 43 in 1990. After travelling the world she came back to Seattle and "saw there were tons of things that needed to be done".

She raised $35 million to buy and restore the beaux arts-style Paramount Theatre which was facing demolition. It is now one of Seattle's showcases.

"The traditional way to do philanthropy," Ida Cole says, "was to wait until you die, but this way you can give not just your financial resources, but your energy, time and talent."