Here is working example with multiple participants:
<?php
$to = '[email protected],[email protected]';
$subject = "Millennium Falcon";
$organizer = 'Darth Vader';
$organizer_email = '[email protected]';
$participant_name_1 = 'Boushh';
$participant_email_1= '[email protected]';
$participant_name_2 = 'Boba Fett';
$participant_email_2= '[email protected]';
$location = "Stardestroyer-013";
$date = '20131026';
$startTime = '0800';
$endTime = '0900';
$subject = 'Millennium Falcon';
$desc = 'The purpose of the meeting is to discuss the capture of Millennium Falcon and its crew.';
$headers = 'Content-Type:text/calendar; Content-Disposition: inline; charset=utf-8;
';
$headers .= "Content-Type: text/plain;charset="utf-8"
"; #EDIT: TYPO
$message = "BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Deathstar-mailer//theforce/NONSGML v1.0//EN
METHOD:REQUEST
BEGIN:VEVENT
UID:" . md5(uniqid(mt_rand(), true)) . "example.com
DTSTAMP:" . gmdate('Ymd').'T'. gmdate('His') . "Z
DTSTART:".$date."T".$startTime."00Z
DTEND:".$date."T".$endTime."00Z
SUMMARY:".$subject."
ORGANIZER;CN=".$organizer.":mailto:".$organizer_email."
LOCATION:".$location."
DESCRIPTION:".$desc."
ATTENDEE;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;PARTSTAT=NEEDS-ACTION;RSVP=TRUE;CN".$participant_name_1.";X-NUM-GUESTS=0:MAILTO:".$participant_email_1."
ATTENDEE;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;PARTSTAT=NEEDS-ACTION;RSVP=TRUE;CN".$participant_name_2.";X-NUM-GUESTS=0:MAILTO:".$participant_email_2."
END:VEVENT
END:VCALENDAR
";
$headers .= $message;
mail($to, $subject, $message, $headers);
?>
If you need to add/remove options here is a reference of VCALENDAR:
VCALENDAR on Wikipedia
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…