Matt,
you can find the tutorial in the "Blender files" file you can download from the first comment here:
http://forum.racesimcentral.com/showthread.php?t=260865
Once you unzip the file you'll find - among others - the file "Build_a_Track.html". that's the tutorial.
Thre forum thread you downloaded the file from also comes handy at times - good questions and good answers.
Before you strat reading or using it, I recommend you to read a tutorial on how to use Blender itself. There are good tuts, this one, for example:
http://www.blender.org/education-hel...face-tutorial/
That one takes like half an hour, not much really.
Another one that might come handy:
http://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro