add appointment to Outlook Calendar

I have a social network built with LAMP. One of the features is a calendar, where I can add events and appointments. As many use MS Outlook I would like to be able to export/sync the appointments I add in the social network to each persons Outlook calendar. It does NOT need to sync from Outlook to the social network The way I want it to work is this: 1. In the social network calendar there is a button "sync with Outlook". 2. When I click it takes all events that previously haven't been synced and add it to the Outlook calendar on that computer. 3. If I do it on two computers then I will get some events on one, and some on the other (That will be the users problem). It is good if it can recognize which computer I used last so that it says "Alert: Last time you synched you used a different computer". 4. It shall export and sync "date, time, location, title and description" 5. It shall show the date I last synched 6. It shall show how many events I have added to my calender that have not yet been synched. When the number is greater than 0, the "synch now?" goes from grey to red. 7. I shall be able to reset previous synchs so that I can get all events synched again. /Peder