Wuh oh – It’s the G4 Cube all over again.

Less than a month after launch, attentive iPhone 3G users have begun to notice nasty little cracks showing up along the edges of the plastic rear casing. It doesn’t seem to be a matter of user-damage, either – even amongst the handsets that have been pampered from day one, cracks have been spotted.

While white iPhones seem to be the focus of the complaints, it may just be because the cracks are more easily spotted on the white surface. At least a handful of Black iPhones have been found to have similar cracks.

There’s a thread over at MacRumors where users are sharing model numbers in attempt to determine if a specific batch is at fault – give it a look if your iPhone is cracking up.