Nintendo would likely cover it under warranty if it is within the right time frame. Hinge cracking around the plastic is a well known defect that sometimes leads to this breakup over time if the crack is on the right side hinge. If Nintendo won't help you, get a new shell and tri-wing screwdriver from dealextreme (should run less than US $20), and do some careful surgery following the step by step guide on GBATemp. In an hour or two, you can have a DS that's as good as new. Get a new right hinge from them while you are at it, just in case your old one is frozen up causing the original cracking and eventual breakup. The most difficult part when I did it wan not the ribbon cable for the top LCD (because the guide covers how to work that through the slots very well). My biggest problem was those springs holding the shoulder buttons. It was a bitch to keep them in while getting the buttons put back over them.
