See the Public Citizen web form action alert;
See the Nuclear Information and Resource Service (NIRS) web form action alert;
See Beyond Nuclear's (and SEED Coalition of TX's) action alert (sample comments you can use to write your own).
Comments had been due by March 13th, but the deadline has now been extended to April 28th. However, please comment ASAP, and more than once, if you have time, on multiple of the many facets of this issue!