Ok.. Here's a compress version by me~ ;p
Exposure: This means the amount of light entering the camera to expose a piece of film... or sensor. Under-expose means too little light resulting in dark pics and over-expose means too much light is enetering the camera, resulting in pics too bright with lost of details.
Shutter speed: one of the elements that "controls" the exposure. In a camera, there's this little hole that allows light to enter the camera so that it can expose the film (or shine onto the CCD/CMOS) The shutter speed indicates the length of time the hole is opened for light to enter. The shutter speed is indicated in seconds. 1/60 seconds is twice as long as 1/125 seconds and thus will allow twice as much light to enter compared to 1/125 seconds
Aperture: This indicates the size of the hole that allows light into the camera. This is indicated in f numbers... A smaller f number indicates a larger hole, a smaller f number indicates a smaller hole.
ISO settings: This is a standardised way of indicating film sensitivity... How sensitive they are to light... Commonly found Film with ISO values of 100, 200 and 400 are commonly found over counters at supermarkets and such... Fuji Superia 100 is an example of ISO 100 film and say Kodak Max 400 is an example of ISO 400 film easily available. More sensitive film, such as ISO 800, ISO 1600 and ISO 3200 can be obtained at dedicated photography shops photography shops. So what does all these means. A high sensitvity film will require less light to expose the film... An ISO 200 film will need half the amount of light to achieve a certain exposure compared to a ISO 100 film. and $00 will require half of what ISO 200 will require and so on... So how does this helps in practice? Sometimes, with low light conditions, and when flash is not desired, one may like to use a more sensitive film so that a faster shutter speed can be used so as that camera shakes (movement of camera during long exposure cause blur images) are minimised. The ISO standards are also brought over into digital cameras... Different ISO is achieved by amplification of the CCD/CMOS signals... As for digital camera, higher ISO will results in more noise, which are random nonsense pixels seen on the final image. For film, higher ISO film generally has poorer resolution and are more grainy.
White balance:Under different lighting condition, the truely white object may not be really white... but this are seldom seen as our brain automatically compensate for the ambient lighting. But for photos, the effect of the colour of the ambient light on the final image is very apperent. In the morning, the sunlight are blue-ish which will results in pictures with blue-ish tint... Fluorescent tubes gives greenish-blue tint to pictures... White balance are available in digital camera to allow for compensating these colour tints.
Er... generally this is what I know lah... Quite basic lah... but hope its informative enough.