The Chronos Date/Time Library is a Smalltalk class library that has its own tz compiler (which compiles tz source into a proprietary time zone format.) There is also a utility that converts Chronos' native time zone files into an XML-encoded representation (http://www.date-time-zone.com/).
 
More information is available from the Chronos web site (http://www.chronos-st.org/)
 
--Alan