$('#calendar').fullCalendar('scrollToHour',integer);

The scrollToHour method takes an integer from 0-23 and scrolls to the
agenda slot representing that hour when in agendaWeek or agendaDay
modes.  An invocation looks like this
$('#calendar').fullCalendar('scrollToHour',9);
Thanks to Philippe.Vosges@gmail.com for the idea, discussed here: http://code.google.com/p/fullcalendar/issues/detail?id=626