Here are some useful links to help you develop your ideas and execute those projects!
 

Project ideas: http://www.all-science-fair-projects.com/category0.html http://www.sciencenewsforkids.org/pages/sciencefairzone/topics.asp http://www.juliantrubin.com/branchesofsciencefair.html
http://www.internet4classrooms.com/science_elem.htm

Using the Scientific Method: http://www.juliantrubin.com/fairguide/scientificmethod.html http://library.thinkquest.org/J001402F/
http://www.utexas.edu/courses/bio301d/Topics/Nonscientists/Text.html http://scifiles.larc.nasa.gov/text/kids/Research_Rack/tools/scientific_method.html http://www.biology4kids.com/files/studies_scimethod.html

Making Your Display: http://www.sciencebuddies.org/science-fair-projects/project_display_board.shtml http://www.stevespanglerscience.com/experiment/00000096 http://www.super-science-fair-projects.com/elementary-science-fair-projects.html http://www.sciencestuff.com/playground/SF-DbSetup.shtml

General Help: http://www.sciencemadesimple.com/
http://school.discoveryeducation.com/sciencefaircentral/
http://www.homeworkspot.com/sciencefair/
http://www.madsci.org/libs/areas/sci_fair.html

Science Sites: http://www.funology.com/
http://www.strangescience.net/
http://www.exploratorium.edu/science_explorer/
http://www.billnye.com/