I agree with Pat. True friends will accept you for who you are. If they leave because of your Atheism -- they were not true friends.
I agree. It’s not worth coming out in the thick of a religious community until you have a good base understanding on how to dispute most of the views in a clear and concise manner. Until then, you could do what I use to do. Explain to them that if they wish to talk about the subject, they are welcome to sit down with you in front a computer, and you can look up their questions together. Much of my family use to HATE when I did that. Keep in mind, youtube is also a great resource to watch debates. Dawkins, Hitchens, The Atheist Experience and AronRa have some great videos, watch their reactions, how they keep the conversations from becoming endless. Its as much a skill to keep them from playing word games and disregarding your answers to throw more endless tripe onto the pile, as it is about facts.