Steve,
I was in the construction field for many years and was laid off for the obvious. I went back to school at the age of 45, and I am now a junior in college getting my BS in IT. As others have mentioned, IT is such a broad field. You really need to get your feet wet to decide what area of IT you want to practice.
Personally, I did not know much about the field when I started. I could search the web, I knew a little about Microsoft Office and Project 2007, and that was it. I just knew that I needed to make a career change and I wanted to chase technology because of its potential. So, after two years of college I still do not know what I want to do, not 100%. Although, I am getting much closer as it is a long road. I recently obtained employment for the first time in the IT field. I got my A+ and Net+ certs from school. However, after working as an IT technician for the past five months, I can tell you that it is not the area I want to pursue. It's just not for me.
I have taken a couple of programming and database (C++ and PowerShell) and I believe that programming/database is the area I should pursue. Security is another area of interest, I will be taking an advanced security class in the fall which will help in the decision making process. However, after talking to some "Experts" in the field, you better be ready to indulge your life into it 24\7, especially in the beginning.
One thing I have found out since working in the field is this. Whatever area of IT you choose... get a degree. Some of the people that have been mentoring me, and people I work with have been in the field for a very long time. They are very intelligent people and know their job well. They started in the business back in the 70's and 80's and are just now going back to college to get a degree because the field demands it. At least if you ever want to get prompted.
The best advice I can give with my little experience is to read, read, read, talk to as many professionals in the field as you can, and take a couple of classes to see if it is what you want.