The link above will take you to DailyTech.com, where you will find a short story to the effect that IE is being separated from Windows. The confirming linke to a Business Week site do not work and I have found no other confirmation at the time of posting.
If this is true, Well over ten years of Microsoft arguing with absolutely everyone about the integration of IE will be over. There may be legal ramifications in the ongoing government supervision of the anti-trust settlement. I doubt it, though. Not least because MS can simply argue that separation was done over time and this is a new operating system being discusses, with much legacy code replaced.
The move also promises to make Vista more secure. The tight integration of the past was a conduit for malicious code to infect the operating system. With this conduit broken, the system itself will be safer by default. And there is no doubt that Microsoft will act to make it safer yet by "sterilizing" the connection between OS and browser. Thus, this move is to their credit. Just how much credit they deserve for it will be apparent over time.