The page doesn’t really explain where to find this. Basically, you need An IRC Client such as mIRC, or the one I use, LeafChat. You use it to connect to the IRC server mentioned at the first link, and join the #speedrunslive channel. From there, it’s just a matter of finding the people to race the race you want to race!
I’m mainly putting this out here because it’s primarily N64 games at the moment. It, frankly, needs more NES representation, like Contra. :P Which I just completed in a bit over 13 minutes, according to RBABot.