WikiAnswers is a good one, but you may consider www.nationalgeographic.com for social studies, and for language arts, your textbooks website
howstuffworks.com is really good for information way better than the others
Hannahmontanazone.com
Coinflation.com and CopperCoins.com are some good sites to research the old coins. Some good sites to research old coins are Coinflation, CopperCoins, and SmallDollars.
Sites are not actually as good as they are ahead
Iconator
brainpop.com
no
lego.com
A good tip for software purchasing, it to do your research before making the purchase. There are many software review sites that list user reviews, where you can conduct a thorough investigation.
morphthing.com
horseisleguides.proboards.com
bpchat.yolasite.com
yes