Jane1:
What PCB design software you use and why
Eagle. I tried ... I think it was five ... others. They were: buggy, limited, difficult to use.
Don't misunderstand me. I really dislike Eagle. But, it works, it has not yet crashed, and I have found a plethora of libraries for it.
What PCB design software you would suggest to start with
If you plan to design one thing over the next few months spend a few minutes to an hour with as many as you can then use the one that worked the best for you. If you plan to design three or more things over the next few months use Eagle.
Are there any GOOD tutorials for that kind of PCB design software
I found several on blogs and instructables.com that help me a great deal.
Are there any support forums for that kind of PCB design software
You can probably get some help here. Beyond that I have no idea.