Idea for Calendar Free/Busy Sharing

Office has a system by which it allows users of Outlook to share free/busy information by publishing it to some service. Since that system is Outlook/Microsoft specific, woudn’t it be nice if there was an internet standard for this sort of thing? Since Calendars these days are strongly associated with email addresses (e.g. my MSN Calendar or my Calendar), it would make sense to publish Free/Busy server information in the public DNS. Much like MX records in DNS tell where to send mail for a domain, I propose that “FB” records tell where to retrieve free/busy information for a domain. It could be implemented as a web service of sorts and a client can query DNS for the FB records for a domain, then contact the FB machines with the email address to find that users free/busy data. Wouldn’t that be awesome?