You'll see Saki soon enough. And no, I don't have an iPhone. And you can make backgrounds transparent in the "Customize My Profile" button. Some modules have the "Transparent" option under the color picker menu.
Honestly, I don't know who she is. I just happened across this picture by complete chance. And, since I love fall (and pretty girls) I decided to make use of it. I'm glad you like it as my background!