You can find a good slr for a decent price used. I got a Nikon D-40 for less than 400.
opens the eye of the camera to let more or less light it
BUT, it also effects how in-focus the background is
high F/stops#=less light, and the background is in focus
low F/stop#=more light, but only the object of focus is actually focused
just what it sounds like, how long the shutter stays open
I'm not sure what the exact definition is, but basically it determines how "sensitive" the camera is to light, so a low ISO makes lights seem dimmer, and high ISO makes them very bright
basically works the same way as ISO in my experience, but the camera won't compensate for high or low values when you input them
i.e. when i change the iso on my camera it will change the aperture or shutter speed to make the picture look the same.....but when i change the exposure comp. they stay the same and the picture gets brighter/darker
This is basically how to get the lighting you want in your picture and make it look awesome.....I'm not sure if you can change these settings in a point and shoot camera. thats why it's best to go with an slr
but i'm sure if you get photoshop then you could get vividly colored pictures with a point and shoot.....not sure about the crispness, that depends on the megapixels of the camera.
so there is a write up by a newbie to photography, so hopefully it's accurate yet easy to understand