Accountant, CEO and executive director of the Maryland Association of CPAs, Tom Hood might not look like the kind of guy who spends a lot of time in an imaginary world. But he does–at work. And he encourages other accountants to do the same. That's because MACPA runs continuing education sessions for accountants in Second Life. Even though the virtual world has attracted its share of press for the zany shenanigans of its virtual residents, like dressing up in crazy virtual costumes, having virtual affairs and speculating on virtual real estate, there's also serious business going on in Second Life–and now, in OpenSim as well.

OpenSim is software that lets any company create its own private, virtual world. What could be a big breakthrough for business users of virtual worlds occurred at the end of June, when IBM announced the release of its Lotus Sametime 3D collaboration product, based on the OpenSim platform.

Celebrating its sixth anniversary, Second Life is the grand-daddy of virtual worlds. More than 200 colleges and universities have a presence in Second Life, as do many corporations, including Wells Fargo, Banco Bradesco, Accenture, British Petroleum and Unilever.