CSSToXSLFO
CSSToXSLFO is a utility which can convert an XML document, together with a CSS2 style sheet, into an XSL-FO document, which can then be converted into PDF, PostScript, etc. with an XSL-FO-processor. It has special support for the XHTML vocabulary, because that is the most obvious language it would be used for. The tool has a number of page-related extensions. It also comes with an API in the form of an XML filter.
The tool has a command-line interface. There are special packages for using it with XEP from RenderX, XSLFormatter from Antenna House, XINC from Lunasil and FOP from Apache. Each of these packages has a corresponding Ant task.
CSSToXSLFO is hosted on SourceForge.
Comments and bug reports are welcome at support@re.be.