I'm a fan of the phones that only call three pre programmed emergency numbers. That way she can reach Mom or the specified neighbor or whatever....but no one else. I think they have kid's phone like that.
My neice got a cell. (she's 14) and she is getting all kinds of wierd people calling her. (one of her "friends" gave out her number)
She also gets calls from a girl she doesn't know accusing her of all kinds of stuff.
I think cell phones are a menace for youngsters....if they can receive calls from other than parents etc.
If the technology exists to only receive calls from certain numbers and only place calls sto certain numbers, it might be workable.
The other thing I have heard from friends is that their kids go over their minutes for texting and by the time they know about it, they owe a huge bill.
I'd drag my feet on this one....
The other issue is the not thinking for themselves one mentioned above. If mom is always available with an answer...they never learn to figure out their own answers. I read a piece on "helicopter parents" which described how always being available to the children did not let them grow to be independent, problem solving adults.
This is a tough situation....and one I'm glad I don't have to deal with
Best of luck!