My iphone keeps sending texts instead of ichat messages?

I know the people I'm messaging have an iphone so it should be going through. Just wondering how to fix that!

Do you mean imessage? Because when you have an iphone both imessage and "regular text messages" are combined together. Others who have iphones can text you through imessage by typing your cell phone number. If you want to text someone who doesn't have an iphone/ imessage, just type in their number in imessage - i think. Or tell them to text you first (using your cell number)