I'm not great about keeping this page updated, but basically everything else I find comes from links, from links, from links that I first found in these links. So check out other pages too if you're looking for something specific, or just click on any of these and start your own treasure hunt for free online resources. There's so much out there. If you haven't tapped into it yet, be patient. It took me a couple months to really start finding what I was looking for, and now I have resources that will last us straight through high school. Good luck!
General Homeschooling advice and ideas, lots of links to other resources
http://www.homeschooling-ideas.com/index.htmlFree Downloadable Textbooks for Middle School and High School (awesome!)
http://www.facebook.com/pages/FREE-HOMESCHOOLING-101/193023227081
http://homeschool.lifetips.com/cat/61481/elementary-homeschool/index.html
Numbers and Letters - Interactive Site
http://www.funbrain.com/kidscenter.html
Math and Science Grades 1-5 - OnlineTextbook
http://pgcounty.scottforesman.com/
Vocabulary - Interactive Site
http://www.vocabulary.co.il/homophones/
Legends, Myths and Fables - Interactive read along or listen
http://www.starfall.com/n/level-c/index/play.htm?f
Online Almanac for Kids
http://www.factmonster.com/
PBS Teachers - all grades, all subjects
http://www.pbs.org/teachers/
Math
http://ocas.pearsonschool.com/sf/0-328-10114-1/iText/products/0-328-10114-1/index.html
http://www.math-drills.com/multiop.shtml
http://mathops.com/free/index.php
Free Worksheets - printouts for all subjects - I use these a lot
http://www.superteacherworksheets.com/
Science -
http://pgcounty.scottforesman.com/
http://ocas.pearsonschool.com/sf/0-328-10114-1/iText/products/0-328-10114-1/index.html
http://www.ellenjmchenry.com/index.html
http://msnucleus.org/membership/index.html
http://www.sciencewithme.com/
Geography
http://www.eduplace.com/ss/maps/world.html
http://www.youtube.com/watch?v=e7t5d0eseIs&feature=related
Where´s Matt? One guy visits 42 countries, getting people to dance with him. We loved it.
http://www.youtube.com/watch?v=zlfKdbWwruY
Great dinosaur site for kids to do their own research
http://www.kids-dinosaurs.com/index.html
Solar System
http://www.kidsastronomy.com/solar_system.htm
http://www.youtube.com/watch?v=HEheh1BH34Q&feature=related
http://www.youtube.com/watch?v=mtKNH2Y2OJM&feature=fvwrel
http://www.youtube.com/watch?v=YMY_-xYmJvE&feature=relmfu
Human Body
http://www.theheadoftheclass.com/Activities/HOCTBodySystems.aspx
Educational videos and Games on all subjects - a bit dated, but helpful
http://www.neok12.com/
Must Visit! Advanced videos - great for parents looking to learn or relearn everything from Solar System to Algebra
http://www.khanacademy.org/
I´ll keep adding as I find more!