The closest Outlook can come to a built-in method for sending a calendar as a single file attachment is to export the Calendar folder to a file, then sending the exported file.
However, if you have Word, you can use one of the Word templates listed at http://www.slipstick.com/addins/calendar.htm#print to push the Outlook data into a Word document, then attach that document to a message.
If you have Visio 2003, you can use the Import Outlook Data Wizard to create a calendar from Outlook data, using a filter to include only certain appointments. The resulting .vsd file can then be sent as an attachment.
For a VBA code solution that creates an HTML-format mail message containing any single day's appointment list, see http://www.outlookcode.com/codedetail.aspx?id=24 .
Another technique is to use a third-part tool called ClipForm (http://www.ivitar.com/clipform/). This tool uses templates to export Outlook data -- a whole folder or selected items -- to the Windows clipboard, text file, HTML email message, or other file types.

Signature
Sue Mosher, Outlook MVP
Author of
Microsoft Outlook Programming - Jumpstart for
Administrators, Power Users, and Developers
http://www.outlookcode.com/jumpstart.aspx
>I need to create a calendar (several appointments) that can be e-mailed to
> external users (out of my company's network). I have tried to export a
> calendar without success.
> Is it possible to do this?
>
> Thanks!
Cecilia - 01 Jun 2005 17:34 GMT
Thanks for your help, Sue. I assume that by exporting a calendar to a file,
it will lose all the functionality, right? (reminders, for example) Is there
any kind of file that I can convert my calendar into that will keep Outlook's
functionality?
Thanks!
> The closest Outlook can come to a built-in method for sending a calendar as a single file attachment is to export the Calendar folder to a file, then sending the exported file.
>
[quoted text clipped - 12 lines]
> >
> > Thanks!
Sue Mosher [MVP-Outlook] - 01 Jun 2005 18:01 GMT
If you export to a .pst file, the recipient can import to their own Outlook folders without losing any functionality.

Signature
Sue Mosher, Outlook MVP
Author of
Microsoft Outlook Programming - Jumpstart for
Administrators, Power Users, and Developers
http://www.outlookcode.com/jumpstart.aspx
> Thanks for your help, Sue. I assume that by exporting a calendar to a file,
> it will lose all the functionality, right? (reminders, for example) Is there
[quoted text clipped - 12 lines]
>>
>> Another technique is to use a third-part tool called ClipForm (http://www.ivitar.com/clipform/). This tool uses templates to export Outlook data -- a whole folder or selected items -- to the Windows clipboard, text file, HTML email message, or other file types.
>> >I need to create a calendar (several appointments) that can be e-mailed to
>> > external users (out of my company's network). I have tried to export a
>> > calendar without success.
>> > Is it possible to do this?
>> >
>> > Thanks!
Cecilia - 01 Jun 2005 20:46 GMT
After exporting my calendar a .pst file, I saved it on my desktop. Then, I
tried to attach it to an e-mail but Outlook doesn't allow it. I get the
following message "Operation failed" Any ideas on how to solve this?
Thanks!
> If you export to a .pst file, the recipient can import to their own Outlook folders without losing any functionality.
>
[quoted text clipped - 21 lines]
> >> >
> >> > Thanks!
Sue Mosher [MVP-Outlook] - 01 Jun 2005 21:00 GMT
You must exit and restart Outlook before you will be able to attach the .pst file to a mail message. Also, you need to either place it in a .zip archive file or change the filename extension from .pst to something else, e.g. .ps_.

Signature
Sue Mosher, Outlook MVP
Author of
Microsoft Outlook Programming - Jumpstart for
Administrators, Power Users, and Developers
http://www.outlookcode.com/jumpstart.aspx
> After exporting my calendar a .pst file, I saved it on my desktop. Then, I
> tried to attach it to an e-mail but Outlook doesn't allow it. I get the
[quoted text clipped - 3 lines]
>
>> If you export to a .pst file, the recipient can import to their own Outlook folders without losing any functionality.
>> > Thanks for your help, Sue. I assume that by exporting a calendar to a file,
>> > it will lose all the functionality, right? (reminders, for example) Is there
[quoted text clipped - 19 lines]
>> >> >
>> >> > Thanks!
Some questions for you:
- Can you send them appointments in iCal/vCal format?
- Are they using Outlook?
- Have you tried exporting the calendar into a PST file?
>I need to create a calendar (several appointments) that can be e-mailed to
> external users (out of my company's network). I have tried to export a
> calendar without success.
> Is it possible to do this?
Cecilia - 01 Jun 2005 17:25 GMT
Yes, they use Outlook.
How do I create a calendar in iCal/vCal format?
How do I export the calendar into a PST file?
Thanks for your help!!
> Some questions for you:
> - Can you send them appointments in iCal/vCal format?
[quoted text clipped - 5 lines]
> > calendar without success.
> > Is it possible to do this?
Vince Averello [MVP-Outlook] - 01 Jun 2005 18:10 GMT
For the iCal thing make sure the "When sending meeting requests over the
Internet, use iCalendar format" is checked here: Tools menu > Options >
Calendar Options
To export into a PST file use the File menu > Import & Export command.
Export to a file and choose "Personal Folder File"
> Yes, they use Outlook.
> How do I create a calendar in iCal/vCal format?
> How do I export the calendar into a PST file?