Well, I've finally got the ball rolling for coming out at work. I'm starting to get some odd looks from my co-workers, and have gotten the "Do you have a cold?" question. Plus, my name change will be official on the 28th, so I figured it was about time.
The HR rep was very nice, and congratulated me on my transition. She also assured me that all the managers had recently gone through "diversity training", which had included "all types of diversity". I gave her a copy of Transgender Workplace Diversity by Jillian Weiss, and we set up an appointment for next Thursday to discuss in more detail how we are going to proceed from here. I think it's going to go well. Wish me luck with my co-workers. I'll post updates as things progress.