My iPhone sending iMessage to non iphone?

My iPhone is trying to send an iMessage to my friend who's phone is not an iPhone. Any help?

That will not happen & even if it does try to it should eventually send as a text message.

IMessage only works between iDevices such as iPhone, iPad, and iPods. Therefore this problem should not exist. If it does send as iMessage then the recipient must have Wi-Fi or network to receive the message.