Don't tell your cell phone any secrets. It might not keep them.

[renovation]

Secondhand phones purchased over the Internet surrendered credit card numbers, banking passwords, business secrets and even evidence of adultery.
Selling your old phone once you upgrade to a fancier model can be like handing over your diaries. All sorts of sensitive information pile up inside our cell phones, and deleting it may be more difficult than you think.

A popular practice among sellers, resetting the phone, often means sensitive information appears to have been erased. But it can be resurrected using specialized yet inexpensive software found on the Internet.

A company, Trust Digital of McLean, Va., bought 10 phones on eBay this summer to test phone-security tools it sells for businesses. The phones all were fairly sophisticated models capable of working with corporate e-mail systems.

Curious software experts at Trust Digital resurrected information on nearly all the used phones, including the racy exchanges between guarded lovers.

a link you may want to read here

[MK888]

That is why I use a phone that is just a phone. None of that email crap, or text messaging.

[FlyingPenguin]

Ditto. My phone is a phone, my PDA is a PDA.