Here is a great starting point for Key Stage Science Resources, for teachers and students.
KS3 Science Links : http://links4science.blogspot.co.uk/
KS3 Science (Bitesize) http://www.bbc.co.uk/schools/ks3bitesize/science/
KS3 Science Wordsearch Puzzles: http://www.ntscience.co.uk/word-search/index.html
KS3 Science Mindmaps : http://www.ntscience.co.uk/science-mindmaps/index.html
KS3 Science Revision (Doc Brown) : http://www.docbrown.info/ks3science.htm
KS3 Science Quizzes : http://www.educationquizzes.com/ks3/science/
KS3 Cyber Physics Revision : http://www.cyberphysics.co.uk/key_stage/KS3.htm
Year 7 KS3 Science http://www.wyedean.gloucs.sch.uk/blogs/science/ks3-year-7/
Year 8 KS3 Science http://www.wyedean.gloucs.sch.uk/blogs/science/science-year-8/
Science Workshop Resources : http://www.ntscience.co.uk/
KS3 Science Revision
(Year 7) http://richardanderson.me.uk/keystage3/year7/year7modules.php
(Year 8) http://richardanderson.me.uk/keystage3/year8/year8modules.php
Resources from www.webucate.org
KS3 Biology and Chemistry SoW + Revision
http://www.webucate.org/ourgallery/thumbnails.php?album=25
KS3 Gifted and Talented Projects
http://www.webucate.org/ourgallery/thumbnails.php?album=58
KS3 Physics SoW
http://webschool.org.uk/science/ks3new/
Levelness Posters
http://www.webucate.org/ourgallery/thumbnails.php?album=60
KS3 to KS4 Transition SoW
http://www.webucate.org/ourgallery/thumbnails.php?album=68
KS3 Physics Questions : http://www.webschool.org.uk/science/ks3/quizzes/
Revision Guides and Worksheets for KS3 Physics