Here is a nice, brief article by one of my favorite bloggers. My favorite part is the blogger's last sentence: Parents concerned about socialization with peers don’t always recognize that the most important socialization is with parents, and begins at birth.
I absolutely believe that this is true. Social skills are primarily learned in the family. The rest of the world is there for us to learn to navigate with the tools given to us by our parents. This is why when some non-homeschooling parents ask me (re. homeschooling), "Aren't you concerned about socialization?" I can only reply, "Aren't you?"