Here is the official download location for the Tecplot output library and source for those of you who want to generate .plt output files.
The current version of the library (December 2007) supports n-faced polyhedra and sharing grids across multiple time steps (in separate files). Its output files are readable by Tecplot 360 2008 or newer.
There was an "off by one" bug in the runtime version of the library that shipped with the Tecplot 360/Focus 2008 products that FORTRAN users might run into. Corrected, precompiled libraries are available for download on the web site.
The Data Format Guide has been extended with more code samples, but we welcome feedback on how we can make this documentation easier to work with.
I've posted the Tecplot 360 2008 R2 linux preplots <a href="http://download.tecplot.com/360/preplot/">here</a>. Older versions (360 2006 release 2) are <a href="http://download.tecplot.com/tecio/360r2/preplot/">here</a>
Finally, if you're using the libraries, please drop Jennifer or me a note.