The whole event kicks off this Saturday, May 3rd over on Cenarion Circle. BRK is organizing the thing along with Ratshag of Need More Rage (he's the one who created the route, and it'll be his friend you're hunting for in Hammerfall). He's got more on his blog, including that the race is a tribute to a friend of theirs who passed away, and all the Tauren will be saying "moo" in respect.
Sounds like a lot of fun. If you want to join them, meet up in Mulgore on Cenarion Circle at 4:00 server time (which works out to 7:00 Eastern). And make sure to take some screenshots. For the Herd!