How Do I Convince My Parents To Let Me Have An IPod Touch?

I have been wanting one for a long time! My dad has the iphone 3G and i LOVE it!!!!! I'm not allowed to have a phone. I was at Tae Kwon Do the other night and I told my sensei that my mom wouldn't let me have a phone. My mom was with me and he told her to get me an ipod touch. I really want the fourth generation not the 3rd or 2nd. But how do i convince them? I don't have chores, get all A's and B's in school, I respect my parents and elders, and i volunteer at the retirement home on weekends and holidays. WHAT CAN I DO??????!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!…