Read about it on the IEBlog.
Install it from http://www.microsoft.com/windows/IE/ie7/default.mspx.
Talk about it on Channel 9.
The IE team started January with one major focus - release this Preview by Jan 31st. We had promised "first quarter 2006" and we wanted to beat that. I'm super happy that we did.
Note that this is not the full fledged "Beta 2" but rather a preview of Beta 2, aimed primarily at site owners, web developers, tech enthusiasts and early adopter types.