I bought a 16GB White iPhone 3G at an o2 store (pay & and go) in December 08. I've had it in a case since then and never dropped it. I took the case off today to clean it and discovered a crack in the casing between the mute tilt switch and the chrome band. I understand this may seem small to some, but anyone looking at the phone can see I've looked after it well, it's in perfect condition and it's a shame that this crack has appeared on a phone I paid £400 for. As it's been in a case, I'm unsure as of when the crack first appeared.

Here's two pics;
http://files.getdropbox.com/u/704227/DSCF2022.JPG
http://files.getdropbox.com/u/704227/DSCF2023.JPG

If the tilt switch seems to be damaged it's just dirt that has collected over the few months I had it

I had that crack in my old 3G. Got it from dropping the phone. It later on got another crack on the other side of the vibrate button toward the mic jack.

Still worked for a long time (months), but also has a rattle inside (if you shake it.)

Moot, as I got a 3GS today.

My friend had a case on it's whole life as well. He took it off and noticed the small crack near the dock connector, the one that many around the forum have seen. He took it to the Apple store and they replaced it no questions asked. This was in the US and it was under warranty though. Thought it was worth mentioning. Hope this helps.

Thanks

If there are no signs of abuse and you are still under warranty, a Genius should issue a replacement.

Both my girlfriend and I have had our white 3G replaced for precisely this cracking issue. It's a very common one, apparantly.