Text messages coming up as iMessages?

When I try to text my friend who doesn't have an iPhone, it comes up as iMessage, so when I send it, she doesn't receive it. Why is it doing this?

Because iMessage uses email to send texts. That's why iMessage is free. Your phone is probably trying to send a text to your friend's email… So next time you create a new SMS, your friends name will show up twice, make sure you select the one with the phone number not the email address. Make sense?