I think you've received some good info on two cad programs.
I would also suggest that you learn some drafting and design terminology. Cad intimidates a lot of people when they open it up for the first time and see things they've never seen before in their lives.
CAD is actually not that difficult to learn if you know the terminology, take time to learn the basics of the cad program on how to draw lines, etc. Once you get that accomplished then learn what you want to do, draw in your cad program.
Also learn some of the basic keyboard commands as how to draw a line, dimension a line, offset a line, etc. Go slow, don't let the program intimidate you, ask questions of people that know cad and forget drawing in 3D unless you use a program like Sketchup and most of all...have fun drafting in cad.
I left the drafting board for cad when it first enter the market. I use several professional cad programs and I can tell you now that I learn something new in the programs just about everyday by chance. It just happens when I'm drafting sometimes.

Good luck and yell if you need some help.