http://www.thecoli.com/threads/it-certs-and-careers-lets-discuss-it.9043/
It's a long, winding thread but a lot of the material you will study for IT certs is long and winding too. Use the search function to pick out posts pertaining to the A+ cert if you're not going to read through the entire thing.
If you've ever taken a machine apart, put it back together, and can identify at least half the components, I'd go with the route of reading through that book, taking notes on each chapter, and quizzing yourself. You can find quizzes online, VCE has a lot of them.
If you've only been an end user (internet surfer, term paper writer, downloading music and movies) then you're going to need to find a computer you can take apart so you can get more familiar with the internals.
Professer Messer has a lot of great tutorials related to the A+ and other certs available on Youtube. Watch some of those. I'm not a fan of how he produced his series, it's recorded like a podcast or a internet course, but they are informative. Dry as hell at times, but he's very thorough and it makes for good learning for a person who's not fully immersed yet.
Best of luck to you. If you have any specific questions I'd go to that thread at the top of this post and ask there. As long as you show that you're not looking for someone to spoon feed you everything, you'll have no problem finding people that are willing to help you on your journey.