10 is definitely not too young to have "the talk". Sexuality has never been a taboo subject of discussion for us. I had the talk with my stepson when he was 10. My son is about to turn 13 and has only just begun the puberty stage, but I had the talk with him at age 10. The rule of thumb in my house is if he's old enough to ask the questions, he's old enough to get an honest answer.
I have several books, a few parenting books that cover the subject and how to discuss it; What's Happening to My Body? - one for girls, one for boys (a little outdated, but useful for kids to read on their own); and The Magic of Sex, which is much more adult (has illustrations, charts and graphs, pictures and loads of info), but covers EVERYTHING. Even though The Magic of Sex is geared toward adults, I've found it to be the most useful because it really does cover everything and I don't forget anything that needs to be discussed. I find books that are geared toward kids quite lacking on the really important subjects, like protection from pregnancy and disease.
The books are great, but only when you sit down with your child and discuss it with him as you read through together. Books cannot replace parental input, especially when it comes to the morals and values you want to instill in your child.
Don't forget to read through any book you get yourself first! If you don't, you can come out sounding like you don't already know and you're just learning as you read with your child. It really makes a big difference if you're trying to teach from the book. Don't let the nerves get to you. Once you've read it, you have the outline for discussion.