I was at a meeting this afternoon with a colleague when his phone vibrated. He looked and said "sweet. Amazon's delivered my new camera lens". How the heck did he get a text message from Amazon about the delivery of his lens?

Okay, this is embarrassing. I was at an important business meeting and as usual, we all put our cellphones in the middle of the table before we started talking. Then a text message from my girlfriend showed up on my iPhone 4 with a, um, suggestive picture of her. My boss grabbed it, read the message out to everyone and raised his eyebrows at the photo. Super embarrassing! Short of telling her not to text me, how can I avoid this kind of situation in the future?

I've never seen this before, but on the icon for Messages on my iPhone 4, there's a small white exclamation mark in a red circle. Not a number indicating how many new text messages I have, but an exclamation mark. Apparently that shows up when something failed. Now what??

In the latest version of Apple's iPhone operating system (iOS), I understand that you can now set custom text message alert tones on a per-person basis, which is awesome: I'll then know who a text message is from before I even look at the phone. Nice. But how do I actually set up these custom alert sounds on my iPhone?

A friend and I were having a beer when her phone beeped: it was a direct message she'd received on Twitter. Cool. How did she set that up and how can I do the same on my iPhone?