Adobe released a beta version of Lightroom 4 today.
New features include support for location data through a map module, book making through Blurb, new video features, new shadow/highlight controls, simplified basic adjustments, new local adjustments, and space saving lossy compression for DNG files. You can find a complete list of changes here. You can downloaded the program for free and use it until the beta version expires on March 31st, 2012.
Photoshop Lightroom 4 Beta [Adobe]