1. Create the appointment and invite required attendees, resources or yourself
2. Send the request. This way you'll be able to keep track of it, and will also have an appointment to export
3. Open the appointment from your calendar, then go to File->Save As
4. Save the appointment as an .ics file. It's a good idea to somehow incorporate the meeting time and/or date into the file name to make it easier to keep track of it.
6. Compose an email to those you want to give the meeting time options to and attach all of the .ics files you created for the meeting.
When the recipients accept the meeting request, you'll receive a response like usual and the meeting will be added to their calendar. The appointment will also be updated in your calendar to show anyone who has accepted as an "Optional" attendee.