This Biodiesel eXtension article investigates different biodiesel production feedstocks.
The U.S. Department of Energy Alternative Fuels Data Center page on bidoiesel.
The Energy Information Administration's monthly biodiesel production report contains biodiesel data compiled from biodiesel producer survey respondents.
The National Biodiesel Board biodiesel production stastics page contains a summary and graph of the U.S. biodiesel and renewable diesel market.
The Wikipedia page for biodiesel production.