Educating yourself is a must that is for sure! The fear of the unknown will get to anybody.

I would thus first suggest reading, reading, and more reading. Read homebirth stories (this is what first made me decide to go with home water birth), read books on all natural birth, read articles and facts on the safety of homebirth.
Homebirth really is safe. I doubt so many would do it if it weren't. Mid-wives are pretty good at educating you and keeping you healthy. I know I felt even better and more exited about my choice when I met my mid-wife Holly. She has kept me in optimal health and there is definately no fear when I go for my prenatals.
I read lots of articles here:
http://www.midwiferytoday.com/articles/index.asp
Here is a good one on waterbirths:
http://waterbirth.org/spa/index.php
I'm sure everyone has many article suggestions for you. There is alot out there. You could probably just search google and find many.
You asked what if something happens. Well, I haven't been through labor yet. I can tell you our "plan". It really isn't much of a plan. If I stay healthy and well till the end we will go ahead with our "plan" of having the home water birth. If for any reason Holly thinks I am too high-risk to have a homebirth she would transfer me to a doctor or simply suggest I give birth in the hospital and not at home. She can treat most problems that arise on her own before and during labor.
If you find a good mid-wife chances are she will have very good prevenentative ways of doing things. Doctors tend to treat after a problem arises (seems more risky to me). I have yet to hear of one who does things anywhere near the way my mid-wife does things.
My mid-wife has a back up plan for the chance anything really unexpected and dangerous goes wrong but like I said, as long as I stay in the health I am in now the chances are very, very slim she can't handle it on her own. The chances are slim there will be anything to handle in the first place.
If anything really bad happens I would be taken by her to the hospital. If we have no time, it would be the ER.
I don't expect birth to go exactly as I picture it but I don't forsee any real trouble. I have taken care of myself (exercise, eating right, taking lots of good vitamins and herbs), I feel strong and ready and am really looking foward to the experience. Birth will be painful but I'm so happy I have the chance to experience in the comfort of my own home.
I don't know if my thoughts are of much help. I hope they help some. Oh, and this is one of my fave articles at that site:
http://www.midwiferytoday.com/articl...ogyinbirth.asp
It is long but it is worth the time it takes to read IMO.