I have a small office set up, and one machine has Vista with Office 2007, the
other has XP with Office 2000. We have been happily using Office 2000,
inviting each other to meetings succesfully, getting automatic entries into
the calendar and replies as well. With Outlook 2007, it looks like a text
string is sent along instead of an invitation, the text is just part of the
email message instead of an actionable link into the calendar with a response
option.

Any ideas what I might need to tweak in 2007 to get Outlook 2007 to work
with Outlook 2000 without an Exchange Server?

Thanks!