There are two interesting domain situations with Microsoft, the actual domain microsoft.com was not at dispute, however two versions have been. First, the domain micros0ft.com with a zero instead of the letter ‘o’ was registered by the company Zero Micro Software which later abandoned the domain after the registration was suspended when Microsoft filed a protest. The domain registration eventually expired and Vision Enterprises of Roanoke, TX registered the domain and apparently expired in 12/2007. Currently the domain is regisitered for another year however the whois domain lookup does not reveal the registrant.
In a second incident, a 17-year-old high-school student named Mike Rowe registered MikeRoweSoft.com. Microsoft then contacted him to give up his domain asserting confusion among the public for a name that sounded like theirs. Long story short, Microsoft now owns the domain name.