GasBuddy.com does publish diesel prices, which are accessed by using the regular gas price charts. When selecting a state or city, the price listings default to regular gas. Selecting the Diesel Fuel tab on the upper right brings up stations that sell diesel fuel, with prices listed low to high.
Once on the diesel screen, the current national and state average prices alternately display at the top of the chart. The latter is for the state currently pulled up in the system. Users may search the entire state or use the Show Search Options link to filter certain station brands or cities. Price information is no more than 36 hours old.