That's a 1/18 standard HPI connector, kind of adopted by everyone as the norm for small scale stuff. I don't know if it has a proper name but I always referred to them as 'large JST's'. In any case I don't like them and prefer micro deans on my 1/18 stuff
Here they are though:
http://www3.towerhobbies.com/cgi-bin...?&I=LXAYU9&P=7