Didn't I speculate that we'll see Indigo before Longhorn a little while ago?
Here's what Eric Rudder says now:
"We have the ability to release Indigo Web services technology and have it run on Windows Server 2003, have it run on Windows XP client and just be included when you install Windows Longhorn," Rudder said. "We haven't decided on a date, but we are going to make Indigo available on other (Windows) road maps."
It may not be Whidbey, but we don't have to wait until Longhorn for the official of Indigo ;)