Unfortunately we only have Nessy as a PC programme and this wont work on the Imacs, I had been trying to find something online to use as an alternative, but it really is such a great resource to use with our KS2 because it isnt regarded as too young for them and it has a competitive edge, in that for each task you complete you are rewarded with nuggets. Anyway great news, I found Nessy online, and it has been updated! You can buy the login for a whole school but we only really need it for at the most 20 pupils, but NESSY have put some of their games and worksheets online and you can play for free, perfect! It can also be used to login at home for £20 a year which is a real bargain considering all the resources it comes with. I shall definately be putting this in the school newsletter for some of the parents to try!
It is also available in an American Version.