Engadget pre-reviewed the soon-to-come-out Blackberry Curve 8520. The highlights are that the trackball works well, but is overall not as nice as the Blackberry Curve 8900. It has EDGE and is probably designed to be for prepaid minute use.
8900 OS sneak Release
An unofficial leak of an OS upgrade for the Blackberry Curve 8900 is stirring up the blogs in the cell phone world. This is an unofficial upgrade for the Curve, BlackBerry OS 4.6.1.231, that is not supported but I guess some people are willing to risk problems to have the latest version.