Ok, his company, Microsoft, has ripped me off several times with rubbish OS, and expensive and unnecessary Office products (use OpenOffice), but I have to say that without Microsoft I may not have found so much of the free and amazing software I use now!
Anyway, that aside, he's creating a new company called bgC3 (Bill Gates Catalyst and 3 is his 3rd project). It's supposed to be a think tank. He is still Microsoft's chairman and is still involved there but has actually "left". This is him branching out and doing his own thing again. It's obviously all computer science and technology oriented research that he has in mind. The idea is that he'll bring together clever people to work on cutting-edge ideas.
This is what labs around the world do, get clever people to work on innovative and cutting-edge ideas and technology. The problem in academia is funding. This is something that bgC3 won't be struggling with I suspect.
Check out Tech Flash more a lot more information.