I tried to put this in once. Do not have a clue where it went?? The house I am in I set up with my entry door being the north door.  After a few years we changed the entry door to the south side. My question is, does it affect all the rest of the house?  Thank you! I hope this one gets out.  I am a new member consta49

Bluntly, yes.  It affects your whole house.  Before you do any entrance changing, find out your kua and best directions.  The Idiot's Guide to Feng Shui is a good beginner book to help you with that.

I am getting conflicting information on which door is actually my Main door.  Lillian Too states in her book that whatever door I use mostly should be considered my main door, but other sources state my Real front door should be used.  I want to do this correctly, my side door faces South with a main road directly facing and my Real front door is faced West by a tall hill which I understand is bad also.

Feng Shui is based on the knowledge of how the flow of chi affects our well being.  Chi flows like wind and water, hence the name Feng (wind) Shui (water).  Chi flows freely through open spaces (open doors, windows), less freely through transparent places (closed windows), and least freely through solid objects.  That is why solid objects are used to manipulate the flow of chi.

One should also remember that there is no such thing as bad chi or good chi, just as there is no such thing as good water or bad water.  There are varying qualities of chi and varying "speeds" at which chi flows, which invariably affects the well being of the person at the receiving end.

Your main door is the one you use most frequently because you open up your house to free flowing chi.  If you keep a door closed, you essentially block the flow of chi.  

Roads:  If the road passes by the front of your home, this is fine.  However, if your house is at the end of a T section facing the road, this is not favourable.  There are remedies for this kind of situation, such as planting hedges in front of your house or building a fence or short wall; any kind of object to slow the onslaught of fast moving chi.

Hills:  Hills are typically better to be behind the house as they prevent chi from escaping from the back of the home.  Again, chi flowing down a tall hill into your home may be harmful because of the force at which it enters into the building.

BTW, Eva Wong's books are very reputable and she offers very reliable information.  You can find out more at http://www.shambhala.com/fengshui/

Good luck!