DAViCal is a server for calendar sharing. It is an implementation of the CalDAV protocol which is designed for storing calendaring resources on a remote shared server. It is a repository for calendar, todo, journal and vcard entries to be accessed via CalDAV clients such as Evolution, Lightning, Apple iCal or the iPhone.
It's a PHP source for a Ical server, require Postgres and http server, and is not also an online service...