For one thing, your photos are all backlit, meaning the light coming from behind your subject is overpowering the light in front of your subject. You camera on auto, wants to meter/read the strong light in the back. Therefore, your subjects are dark. Using a flash will help fill in the light in front (yes even on a sunny day outside, I use a fill flash to reduce shadows on my subjects). The other thing you could do is focus on your subject, press the shutter half way down so the camera can meter the light there and adjust itself, then continue to push the shutter all the way down to take the picture.
Your shots are a bit blurry too. Again, the flash will help with that. Try taking your camera off auto, and set it to P mode (program). It is like auto, but you can adjust a few things like ISO, and aperture. If you don't want to use flash, this will help. ISO is your "film" speed. You would use 100 on a sunny day, and move up from there depending on your lighting. However, the higher you go, the more "noise" will show up. Noise makes the photo look grainy. Most cameras these days handle noise much better than they used to, so you could push the ISO. If you use post processing software (ie Photoshop), you can also remove this noise to some extent.
The best place you start to learn about your camera is its manual. From there, search the boards as there a tons of advice on settings, etc. Check out your library or book store on basic photography as well. Look into your local community college or rec center as well as many offer basic photography classes. I basically taught myself that way, starting at a basic camera and working my way up to a dslr (GASP! I was really scared about that move). A few years ago I took a photo certification course at the local college and gained so much from it.
