The IE team have announced on their blog that when it is finalized, IE 7 will be pushed out via Windows Update. It also explains what to do if you or your company DON'T want it. You have a little while to act because this isn't going to happen until the fourth quarter of the year: expect IE7 to be released at roughly the same time as Windows Vista.
The user experience of IE7 is superior - at the conference this week most of the machines set up for Kiosk style use are running XP, with Office 2003 and IE6. Having grown used to Vista, Office 2007 and IE7 going back feels crude and clunky. The security is better with the phishing filter, fix my settings and Active-X opt in (and better handling of SSL too). Personally I think everyone should have it, but it would be wrong to force people, hence the opt out.
Bonus link. When I was reading the story on CNet the page had a link to an artist who uses the same he receives as the seeds for his computer generated art. Some of his pictures remind me of the stuff I saw when I was diving last week.