Here is my favorite site on BASIC composition-there is far more to it than this, but these are the very basic rules and will always serve you well.
Guidelines for Better Photographic Composition.
Keith (KmH) has some awesome links in his signature to help you get started with exposure and the creative controls of exposure.
You NEED to get a calibrator. The Spyder3 Express is like $60 or something. It's an absolute must if you are working with photos or you have no REAL idea what you are creating until you get a print back from a reputable lab and realize it's horrific.
Here's my advice when learning: Do not add flash until you understand the exposure triangle and how each piece of it controls the exposure as well as the creative aspects of the image. Flash changes some of the rules and will make it complicated. First learn exposure, then learn flash.
That doesn't mean don't use flash ever, never... whatever. You will have to use it at times-you aren't going to quit snapping photos of your kids and life. But in your learning practice and work leave it out for now.
Concentrate on how each of those 3 elements work separately. When you are working on aperture shoot in aperture priority, shutter priority when working on shutter speed. Then start into manual and how to combine them to create the image and the exposure. You don't have to shoot all manual all of the time. MANY photographers are shooting in priority modes almost all of the time. In order to do that you have to understand what that mode is controlling for you and how it will change your photograph-hence learning how to shoot in manual.
When you have a fair understanding of what each element will do, then move on to flash with an external speedlight.
You can learn post processing through all of this, but do not concentrate on photoshop or gimp or whatever you are using. It's a crutch that can totally ruin your growth in camera if you think "I can fix it in PS."
Ask questions. This forum is blunt and to the point, but there is an amazing amount of knowledge exchanged here freely every day and they all will help you. If there is someone you just can't stomach-there is an ignore button or simply pay no heed to them.
Ask for CC. In order to get the best CC back from us you have to give us some info-your settings on the images and what you were working on or trying to do. What you think you screwed up and any questions you have for helping you achieve whatever it is that you think you aren't quite nailing. Be well aware that we aren't going to be like your friends, family and facebook where you are told you are the Greatest Ever. We are going to give it to you straight up with no chaser. However it's those wrong things that we are going to help you to change and learn how not to do or how to fix.