Need to refresh your knowledge of a particular topic then these might help.
My youtube channel has revision videos for year 7 through to year 11. Click on the picture above to link to it.
Mr Hegarty Maths is an excellent maths revision resource on youtube.
Another excellent GCSE revision website is Corbettmaths.com You can find excellent revision tutorials and loads of practice GCSE style questions on hundreds of topics.
I will also be using http://www.sumdog.com this year with all key stage 3 pupils. Each pupil has been given their username and password for this and should have written it in the maths section of their planner and on the front of their maths book.