There is an article on Linux.com (written by Colin Beckingham) that outlines the steps the author took to create a small system that can query a database using speech ... with help from HTK, Julius, Audacity, Festival and the VoxForge tutorial and howto.   From the introductory paragraph of the article:

Though the tools for voice control and dictation in the open source world lag far behind those in the commercial arena, I decided to see how far I could get in querying a database by voice and having the computer respond verbally. Using a number of open source tools, I'm happy to report success.

--- (Edited on 5/16/2008 1:21 pm [GMT-0400] by kmaclean) ---

--- (Edited on 5/17/2008 2:55 pm [GMT-0400] by kmaclean) ---