Hi Mindy. I really don't have any suggestions for you because I've always worked in larger corporate setting. So for me, the only person I told -- and felt obligated to tell, was my direct boss. I was only ever pregnant once while employed, and fortunately for me, my boss took it rather well. He was quite surprised, to say the least, but he took it well nonetheless. If I recall correctly, I told him we needed to "start thinking about someone to take my Program over for a few months.". He asked why, I responded, because "I'm going to be out on maternity leave beginning in October." He said something like "No, really???". I said, "Yup, really." I did this over the phone because he was located in Philadelphia and I was in Northern Ontario where the company relocated me to about 6 mos prior. Also, in Ontario, people get one year paid maternity leave so that's why I told him we needed someone to take over for me "for a few months". I know it's quite different in the States...
I think it really depends on the relationship you have with your boss. I had a great relationship with mine so it was relatively easy for me to break the news to him. Not sure that I was much help to you, but I wish you the best regardless of how you announce the news to him. Please let us know how it goes. Best wishes to you.
I have a really good article on what to consider before telling your employer you are pregnant: http://parenting.ivillage.com/pregnancy/pwork/0,,p94p,00.html?ice=iv:mb:msg:rk
Since you have a unique job situation, not everything in the article applies to you, but I do think there is really good information about knowing your rights, having a plan, etc.
I think your friend gave you great advice to CC someone on your e-mail because it's a good source of protection.