Will Apple replace my iPhone 4?

Only Apple can answer that.

Spontaneous screen breakage may be a tough sell, but who knows maybe they will allow.

Normally, apple doesn't cover screen damage under warranty, regardless if it was your fault or not. You will have to pay $199. + Tax to replace your phone. However it up to the genius to determine whether to charge you or not. Some have reported that they got theirs replaced for free, others weren't that lucky in trying to get it replaced for free. You might as well give it a try and be very polite and tell them what exactly happened.

Okay idk in your case if it is possible, BUT.. when I camped out for the IP4 and i dropped it on the cement about 2 times.. I had TINY cracks in the left hand corner.. I talked to apple care and he suggested to me to claim it could of been over looked in the warehouse..

It is all about how you approach it, be smart, be kind... idk they replaced my phone!!! I was happy. But i think it was because he recognized me from the camp out lolol

Let me begin by saying I'm not a huge Apple fan and the Iphone is the first product I have bought since my Apple IIE as a kid. That said, I dropped my I4 on the ground, broke the camera, etc... and the Apple store simply provided me a new one without asking questions, etc.... Now it was within 30 days but I would just go the the Apple store and talk to them.

Make a genius appointment, take it to the Apple Store and tell them what happened. I dropped mine a couple weeks back (got it on launch day) and had a diagonal crack on the front screen. Genius looked at it and did a one time replacement at no cost. Took about 10 minutes total.

Good luck.