On Facebook, there is the Ramen In Common group and also the Chow Down in Chinatown group. If you are on Facebook, be sure to ask to join both groups.
Here are recommendations from the groups:
Ichiro Sapporo Ramen (recommended by food explorer, Michael Shum)
Jinya Ramen Bar (now in Mid Town and other locations)
Ramen Bar Ichi
Shin Jin (in Cypress Fairbanks)
Shokku Ramen (soon to open in the Woodland Heights on Studewood)
3 Little Pigs for shoyu ramen (Katy)