http://www.bbc.co.uk/education/subjects/zqhs34j BBC Key Stage 3 Maths

http://www.bbc.co.uk/education/subjects/z38pycw BBC Key Stage 4 Maths

http://www.topmarks.co.uk/Interactive.aspx?cat=30 Key Stage 3 Maths activities from Topmarks

http://www.topmarks.co.uk/Interactive.aspx?cat=138 Key Stage 4 Maths activities from Topmarks

http://mathforum.org/dr.math/ Ask Dr Maths a question

http://www.counton.org/ The Counton site, lots of resources

http://www.worksheetgenius.com create free, randomizable maths and literacy worksheets

http://www.mathfactcafe.com/ generates worksheets

http://www.whiteboardmaths.com/ Mostly to buy, but some free PowerPoint resources