Lucas' Pure3D Editor is a tool for opening Pure3D (.p3d) files found in various games created by Radical Entertainment.
The tool is primarily geared towards loading Pure3D files and chunks for The Simpsons: Hit & Run with only partial support for chunk types found in other games.
This tool is available from the Donut Team downloads page.
See this page for the editor itself.
See this page for the Model XML Blender Add-on.