I just thought I'd share the websites that we use around here sometimes, for supplementing school:
Starfall : Great for learning to read, calendar skills, etc. Love this for the little ones!
Funbrain : We use this mostly for math facts, but there are language arts games on here as well.
Vocabulary and Spelling City : Definitely check this out! You can supplement or do your whole spelling/vocabulary program on here.
Fun 4 The Brain : We use this mostly for math facts also, but there are some other things on here also. Fun games!
Multiplication.com : Great for multiplication facts!
Sheppard Software : Games for all subjects! We love this for geography, especially for working on states and capitals.
Big Brainz : Not exactly online games like the rest of them, but this is the BEST! Absolutely the best game for multiplication facts, and they're finally developing games for the other three operations. You can download the free version to try it out, and it is totally worth the money to buy the full version, especially if you have several children that it will go through.
I hope you enjoy these. Happy homeschooling!!