I have a lot of favorite homeschooling websites. Here are a few.
There's Google of course, as in "I don't know how many vertebrae a bird has, let's Google it." (Different species of birds have different numbers of vertebrae! Who knew?) I don't even want to think about how many google searches a day we average!
When I'm helping new homeschoolers, I always point them at Home Education Magazine's website, and remind them to check out the getting started page.
Then there's the International Children's Digital Library. How cool is that?
Living Math has been a wonderful resource for us. I only wish I had a larger book allowance (both space and money) because some of the books recommended here are hard to get through our local library.
Then there's the BBC school website. My oldest (9) has enjoyed playing some of the games on this site, most notably Dance Mat Typing.
These are just a few of our favorites. What are yours?
As a little aside: I do limit the amount of time the children have to play on the computer, even if the game is educational. I find that more than ~30 min. of screen time tends to lead to poor behavior. Also, for at least one of my kids, the draw of the computer is so great that all other activities will be pushed aside and forgotten if computer time is unlimited. So much for unschooling, eh? Every family has to work out what is best for them.