Bob McCown writes: I manage several websites, both internally and externally accessable. Many of them have event calendars or schedulers. We'd like the ability to have these calendars shared and modifyable by both a web interface and at an application level (i.e. a Sunbird or Outlook plugin, or similar). The web side of it is Enterprise Linux running Apapche. Ideally the web side would be written in PHP, to minimize time to integrate with the rest of the sites. What's out there that can do this? What have you used before? Inquiring minds want to know!