OmniHelp is a cross-platform, browser-independent, tri-pane help viewer built in pure JavaScript and CSS with HTML 4. Some functions (such as help embedding) may in the future be in Java, C, or C++; CSH is fully supported. All code is under the LGPL.
PHPSCH is php based source code syntax highlighter. It supports php, c++, c#, java, delphi, css, html, mysql. You can change the default syntax colors with yours. project page: www.ibonette.com/phpsch-source-code-highlighter-kaynak-kod-renklendirici
UniView is an universal image, text and multimedia viewer (and editor). It supports many formats, contains plugin technology and a few interesting features (like javascripting). Distributed under GPL v2 :-)