There is already a plugin to save the attachments.  And calendars are already saved as iCal files. Can you explain your requirement a little elaborate ? Thanks.

The requirement is:
- sending vcards or images directly to devices, or via IM without needing to save the file locally, find it in the file chooser, and then send it.

For example, sending a vcard from an e-mail to a phone takes at least 3 steps:
- save to the local disk
- find the file on the disk
- right-click and select "Send to..."

With such a plugin, I could right click on an appointment, or a contact, and select "Send to...", select a device to send it to, and have it appear on the device.

Bastien,

evolution/plugins/import-ics-attachments could be a sample plugin. It sort of does the same thing, but imports them somewhere else.

    	<hook class="org.gnome.evolution.mail.popup:1.0">
		<menu id="org.gnome.evolution.mail.formathtmldisplay.popup" target="part" factory="org_gnome_evolution_import_ics_part">
		</menu>
	</hook>
    	<hook class="org.gnome.evolution.mail.popup:1.0">
		<menu id="org.gnome.evolution.mail.attachments.popup" target="attachments" factory="org_gnome_evolution_import_ics_attachments">
		</menu>
	</hook>
	<hook class="org.gnome.evolution.mail.popup:1.0">
		<menu target="attachments" id="org.gnome.evolution.mail.composer.attachmentbar.popup" factory="org_gnome_evolution_import_ics_attachments">
		</menu>
	</hook>


	<hook class="org.gnome.evolution.calendar.popup:1.0">
		<menu target="attachments" id="org.gnome.evolution.calendar.attachmentbar.popup" factory="org_gnome_evolution_import_ics_attachments">
		</menu>
	</hook>

^^ are the hooks that needs to be looked at. 

I'll take a look at this in greater detail later on. Thanks for the pointers.

2009-02-18  Bastien Nocera  <hadess@hadess.net>

        * Makefile.am:
        * configure.in:
        * evolution/Makefile.am:
        * evolution/nautilus-sendto.c (popup_free),
        (org_gnome_evolution_send_file_attachments),
        (org_gnome_evolution_send_file_part), (send_file):
        * evolution/org-gnome-evolution-send-attachments-to.eplug.xml:
        * evolution/plugin.mk: If evolution-plugin is available, compile
        a plugin for Evolution to allow sending arbitrary attachments through
        nautilus-sendto (Closes: #511685)

2009-02-18  Bastien Nocera  <hadess@hadess.net>

        * POTFILES.in: Update for latest changes

Reminder to myself to update nautilus-sendto when Evolution's kill-bonobo branch gets merged.  This will replace the "org.gnome.evolution.mail.popup" hook class with a new class named "org.gnome.evolution.ui", so plugins everywhere will have to be updated.