Engadget just finished the final part of their series on making your own HD projector.
Building your own projector isn't a new idea. Disassemble a desktop LCD display, put a really, really bright light behind it and add some optics and voila! you've got a projector. The real question: is it worth it? Since you might be a little leery of dropping several hundred dollars on parts and gutting a nice display because people you don't know on an online forum said so, we're going to do it for you..