What does Carrier IQ do?
I did a little googling and it sounds like carrier IQ is capable of recording and transmitting everything that happens on the phone, including text messages and keystrokes. I emphasize "capable" because the company line is that they just do what their clients (i.e. AT&T, LG etc) ask. It's mostly a privacy issue.
My personal view is that if you are really concerned about privacy then your best bet is to root your phone and scrub it down. Even then you're still using the carrier's cell towers so there's only so much you can do.