Outlook 2007 has this feature.

Signature
Sue Mosher, Outlook MVP
Author of Configuring Microsoft Outlook 2003
http://www.turtleflock.com/olconfig/index.htm
and Microsoft Outlook Programming - Jumpstart for
Administrators, Power Users, and Developers
http://www.outlookcode.com/jumpstart.aspx
> Often I am involved in trying to set up conference calls from people across
> the US and everyone is asked to share their calendars. It would be nice to
> be able to just copy the calendar and send it as part of e-mail. Instead I
> have to put down M and times available, T and times available ....