I wrote a BB based diary application for a conference last year.  It allowed delegates to view conference sessions and search for speakers etc.  Updating it recently I wanted the users to be able  to add calendar entries.  This is pretty straightforward.  There's a code listing below but before that a step by step in plain english

1. Get an Eventlist instance for reading and writing
   
2. Create a new event and give it a title and location
   
3. Use a Java Calendar instance to create a date/time in a particular timezone (One for the start & reuse for the end)
   
4. Use an AddEvent call to set the start time and another to set the end time
   
5. Create an alarm for the event
   
6. Commit the changes and close the Eventlist

I chose to add the "Add to calendar" function to a menu item.  The menutiem is available when the delegate views any session.  It takes two clicks to add a session to the calendar.   It would probably be nice to check for conflicts too I suppose.

The code with some inline comments follows.  If this were a real menu item it ought to create a calendar entry for January 21st 2007 14:00 - 14:35 hours and create an alarm associated with it.

Hope it's of interest,
Jason

private MenuItem _addSession = new MenuItem("Add to Calendar", 120, 10) {

       public void run() {
        EventList eventList = null;

        try {  
        // the catch clause is at the the end of the new MenuItem

        eventList = (EventList)PIM.getInstance().openPIMList(
        PIM.EVENT_LIST, PIM.READ_WRITE);
      
        Event event = eventList.createEvent();
        if (eventList.isSupportedField(Event.SUMMARY)) {
           // I'm getting the title from a field on the screen that's being viewed
           event.addString(Event.SUMMARY, Event.ATTR_NONE, _titleField.getText());
        }      

       if (eventList.isSupportedField(Event.LOCATION)) {
          // I'm getting the location information from the screen too
           event.addString(Event.LOCATION, Event.ATTR_NONE, _locationField.getText());
        }

       java.util.TimeZone tz = java.util.TimeZone.getTimeZone("America/New_York");
       java.util.Calendar calendar = java.util.Calendar.getInstance(tz);

       // In this section we are constructing the start time for the event
       Calendar c = Calendar.getInstance();
       c.set(Calendar.YEAR,2007);
       c.set(Calendar.MONTH,Calendar.JANUARY);
       c.set(Calendar.DAY_OF_MONTH,21);
       c.set(Calendar.HOUR,14);
       c.set(Calendar.MINUTE,05);
       c.set(Calendar.MILLISECOND,0);

       if (eventList.isSupportedField(Event.START)) {
        event.addDate(Event.START, Event.ATTR_NONE, c.getTime().getTime());
       }

       // In this section we are constructing the end time for the event
       c.set(Calendar.HOUR,14);
       c.set(Calendar.MINUTE,35);
       c.set(Calendar.MILLISECOND,0);

       if (eventList.isSupportedField(Event.END)) {
       event.addDate(Event.END, Event.ATTR_NONE, c.getTime().getTime());
       }

       if (eventList.isSupportedField(Event.ALARM)) {
           if (event.countValues(Event.ALARM) > 0) {
           event.removeValue(Event.ALARM,0);
           event.setInt(Event.ALARM, 0, Event.ATTR_NONE, 396000);
           }
       }

       try{
           if(event.isModified()) {
           event.commit();
           }
           }catch (PIMException e) {
           // Handle exception.
           }

       try {
           eventList.close();
           } catch (PIMException e) {
           // Handle exception.
           }
      }

       } catch (Exception e) {
       // Handle exception.
       }

   };