Smileys sent from droid don't show up on iphone?

I have a droid (RAZR) and my friend has the iphone 4. All of the smileys she sends me pop up as the little green aliens. (when i say all i mean; happy, sad, concerned, and kissy faces) but, any smileys i send to her stay in text format. Is there an app for droid that can fix this problem?

I don't think so I've tried it before but couldn't do it. An android phone shows smileys in an android phone but iPhone doesn't