Hi all,

I am looking for suggestions for a calendar/scheduling tool that I can integrate with a CodeIgniter PHP application.

A little background - Im developing an application that has a scheduling component. The application is for a Nutrition Education department within an org. It should allow the a user to schedule and manage Nutrition Education classes. The user needs the ability to invite other users to classes and determine the availability of other users schedules.

Some of the tools Ive looked at -
phpScheduleIt - phpScheduleIt : Open Source Web Based Resource Scheduling
Smart PHP Calendar - Smart PHP Calendar - User Friendly Calendar/Scheduling Software
Google Calendar API - https://developers.google.com/google-apps/calendar/
dhtmlxScheduler - JavaScript Event Calendar - Ajax Scheduler - dhtmlxScheduler

I've had little luck finding anything that suits my needs. Google Calendar API is great and has a lot of the features I need, but I also need the ability to easily store that data in my server and not simply interact with Google Calendar. Smart PHP Calendar seems promising, but they also are very small and seem to lack support.

Are there any large software vendors that offer a product like this?

Thanks for any help you can give!