The deal covers the final stages of construction as well as the first four years of Wembley's operational life. The stadium will seat 90,000 people and is due to host its first event, the FA Cup Final, next May.
Other sponsors to have signed up include Npower, the official energy supplier, and Betfred, which has the title of official bookmaker for the stadium. The deal runs until 2010.
Nick Barley, business and marketing officer at Microsoft, said: "Microsoft believes in helping people to achieve their potential. Wembley Stadium plays a unique role in British life -- it's a national icon that has inspired generation after generation of young people with the dream of playing and performing at Wembley. By becoming Wembley Stadium's first founding partner, we are helping to ensure that dream continues."
More than 2m visitors are expected at Wembley every year, and its redevelopment is estimated to create around 5,000 jobs, which is part of a programme that the London Borough of Brent has called "Vision 2020" to provide improved transport, housing and leisure facilities in the borough.
It will host events including the Rugby League Challenge Cup Final and be home to the England football team. Live music will also feature prominently, with Bon Jovi due to stage a concert there in June next year.
Corporate hospitality is already proving a boon for Wembley, with sales topping the £3m mark and three of the five sections of the Club Wembley programme's gold and silver seats having sold out.
Michael Cunnah, chief executive of Wembley Stadium, said: "The union of Microsoft and the new state-of the art Wembley Stadium is fantastic news and will help resurrect the stadium as the world's leading sports and entertainment venue."
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