Oregon-ballot-box-locator is a project mainly written in Ruby, it's free.
This is a sample application for the Data.Oregon.Gov Open Data Website, built using the Socrata Open Data API and Tropo.
To try it out, call (206) 397-0774.
For more details on a similar app, see my blog post at http://dev.socrata.com/blog/2010/10/28/making-government-data-accessible-by-phone-using-soda-and-tropo/.