Auto mode: Sets every thing for you.

Portrait mode: Automatically sets your aperture.

Macro mode: It helps with close up pictures.

Landscape mode: This gives a a huge depth of field.

Sports mode: Helps with moving objects.

Night mode: Helps in low light situations.

Movie mode: Can capture moving images.

A or AV mode: You chose aperture the camera choses the rest.

S or TV: You chose shutter speed camera choses the rest.

Program mode: Like auto mode but a little more control.

Manual mode: You have full control over the camera.