I have found this site to be very useful. The tutorials are easy to follow and they make the visualization of cell division very clear. I have used this website in the classroom while doing a lesson on Mitosis and the students really enjoyed the fact that they could see exactly what was happening during it. I would recommend this site to any biology teacher or biology student.
The site was fairly easy to follow. Not as professionally done as some, but that didn't detract from its usefulness.