it is possible but not easy.
http://jimblackler.net/blog/?p=151&cpage=2#comment-52767
and
private void InsertAppointment(String strTitle, String strDescription, String strEventLocation, long StartDateTime, long EndDateTime, boolean bAllDay, boolean bHasAlarm){
int tAllday;
int tHasAlarm;
if (bAllDay = true){
tAllday = 1;
}
else
tAllday = 0;
if (bHasAlarm = true){
tHasAlarm = 1;
}
else
tHasAlarm = 0;
ContentValues event = new ContentValues();
// Calendar in which you want to add Evenet
event.put("calendar_id", CalId); //CalId
event.put("title", strTitle);
event.put("description", strDescription);
event.put("eventLocation", strEventLocation);
event.put("dtstart", StartDateTime);
event.put("dtend", EndDateTime );
event.put("allDay", 0);
event.put("hasAlarm", 0);
Uri eventsUri = Uri.parse("content://com.android.calendar/events");
// event is added
getContentResolver().insert(eventsUri, event);
}
a quick search on
content://com.android.calendar/calendars
will help get you started. but I'm not finished mine yet I just can't get the data out yet. but it is possible