School contacts are scheduled but for the best results set a scanner on 145.800 FM and listen. SSTV, packet and voice. Have not heard packet lately but both SSTV and voice within the last 30 days.
but they haven't really been following the schedule much! You can also see what others around the world have been hearing at http://oscar.dcarr.org/ That will gaive you a good idea of what's going on. Also try the ISS Fanclub site.