My daughter is 12 and was given a mobile phone about 2 months ago. The terms and conditions of the usage of such phone is to contact mom / dad incase of emergency. mxit has been allowed but limited to friends being contacted only and no participation in any chat rooms (was not aware of the legislation that says children under 14 are not to have phones with internet access). Mom/ Dad can monitor phone when and if deemed necessary and go into her mxit account, sms's, call logs etc.
Does she abuse the phone? yes on occassion, but when told to put it away she does.
She has a phone because I know I have brought her up to be a mature responsible person.. at 12 she is no longer a child.. nor is she an adult.
My son who is 9 is also looking for a phone, but alas my husband and myself do not see him as responsible or mature enough and he has been sat down and explained. When he reaches some milestones in regard to responsiblity and maturity then yes, he too will get a phone, but he knows he needs to prove that he is mature and responsible enough first. If this means he gets a phone when he is 16 then so be it.
There are many scources of terror in the cyber / mxit/ facebook world for all parents, but so is there in malls, parties, sleep overs etc. You know your child better than anyone else, if you believe they are mature enough, if you have the relationship with them that they can openly speak to you should something "funny" be said to them then allow them to grow in their new found responsibilty of maintaining a phone. If however you believe they are too young in mind and heart to own a phone.. then I would go with your instinct and not give it to them because you as a parent know best. It is not age that determines this, it is trust, maturity, capability of handling responsibility and open relations with your child. For some this may be 10, for others this may be 16.