If you'd like to register your support for the American grizzly bear ... write. Letters are extremely important; they show that you care enough to take a few minutes out of your day to sit down with pen and paper and speak your mind.
Your best bets for getting action seem to be Congress and the Interagency Grizzly Bear Committee (IGBC). The latter is a group that includes representatives from the U.S. Forest Service, the U.S. Fish and Wildlife Service, and the Bureau of Land Management, plus the directors of the wildlife agencies of the grizzly states: Montana, Wyoming, Idaho, and Washington. And even though it's represented in the IGBC, the Forest Service is worth a separate letter, since it manages 63% of all grizzly habitat in the lower 48 states.
If you do write, the Great Bear Foundation would appreciate seeing a copy of your letter, or a copy of any reply you receive.