Here's a brand new website that I finished creating this week that I'm sure you'll want to share with your colleagues, children and parents:
Made by me, my deputy head @mrmkemp and a few Year 6 children from my school, Parkfield Primary School, it contains a series of maths tutorial videos explaining how to progress and improve doing: addition, subtraction, multiplication and division calculations.
The videos have been recorded using the Educreations app on an iPad - they can be viewed via Flash on a PC or opened up in the free Educreations app on an iPad (I'm led to believe that an iPhone/iPod Touch version is coming soon).
You can use the website to ensure that there is a consistent approach to teaching calculations at your school and use it in lessons as a tool for children to independently access for support, such as when completing a calculations sheet like this:
I hope you find this site useful!