Kompozer is now the only free tool that can match Dreamweaver's WYSIWYG layout chops.
Once there were many free drag-and-drop web-authoring tools, but as the web became more complex they gradually disappeared.
Kompozer has a convoluted history. It's based on Nvu, a defunct drag-and-drop site-authoring tool that was in turn based on Netscape Composer.
Using open-source code released by the Mozilla project, the Nvu team added extensive CSS support, site management tools, coding views and document-navigation aids. It's similar in operation to pre-MX versions of Dreamweaver, but with support for more current web standards such as XHTML 1.0.
While Nvu had functionality, it lacked friendliness. Kompozer has improved the interface while adding CSS-editing tools, FTP and tabs for organising the workspace.
It's a pity, then, that development on Kompozer appears to have been frozen. It's now the only true drag-and-drop HTML-authoring tool in the public domain.