An article in the Times claims that half of young children now have their own mobile phone, and manufacturers are planning on targeting a handset at children.
I personally only know one 9 year old with his own phone. He uses it to call his Dad who lives apart from his mother. I'm not sure how accurate this article is.
My dds will be getting a phone when they go to secondary school and not before. I'm still rather nervous about the risks of using a phone. I'm also nervous about how much money dd1 will be spending on calls and texts.