hoserab
I put 'em at the node in the middle, and tag the crosswalk nodes as "crossing=*". There's some controversy as to what exactly people are *supposed* to do in this situation, but I think it's implied that if there are signals in the middle of the intersection that they will also control the pedestrian crossings in concert with the vehicular traffic. I.e. in no case would a pedestrian have the right-of-way to cross an intersection in front of a car that has a green light.

Unfortunately the pedestrian crossing tagging schemes are a hodge-podge of British gobbledygook about zebras, pelicans, toucans and other exotic animals that is slowly becoming more standardized for the rest of the world.