Nothingness:
Click "New game"
Click "Other"
Click "Espionage"
Change the drop down box set with "100," to "1900"
Uncheck the "Include unrated players" box
Click "Continue."
Click "Send"

I think BrainKing uses a less transparent rating system than that: http://math.bu.edu/people/mg/ratings/approx/approx.html