Study Dog is a program for ages 4-9 to teach phonics and aid with struggling early readers. It is adaptable to each child and very entertaining!
The best site I have seen is created by the Discovery Channel. The link is discoveryeducation.com. It is an unbelievable site of help in all subjects and grade levels. There are free videos and help. You can simply put in a math problem you having a hard time with and it will walk you through it. There is a login, although you can get to most everything without one. Your child's school may have a passcode to use for the site, but when I went into it, I was able to access most everything without one. You have to try this site if you haven't seen it.
Hot Homework Tips for Parents this article gives some great suggestions for getting homework done. This whole website has a lot of information. It is given in a clear and easy to understand way. There are a lot of different subjects. The home page is Parenting Bookmark. I will have this site on other pages and topics.
Great website for ideas on Science Fair and other Science Projects in all grade levels.
Ideas for making a diorama. On the bottom of this page are listings of many different things to make of different subjects and topics.
Video tutorials of how to make a diorama. On the side bar, are many other how to videos. You can find how to make or do a lot of things through this site homework related and otherwise.