Some quick tips (from an S3 owner):
1.) Use P mode as a general "walking around" mode; the camera is almost in Auto mode, but you can control the ISO and have access to all of the other features in the Func menu. Keep the ISO as low as possible for the given lighting conditions and avoid 800 unless you absolutely *need* the shot and are willing to put up with the noise/NR software.
IMO, when it's bright the S3 overexposes just a little, so I usually set the Exposure Compensation (with the FUNC button) to -1/3 or -2/3.
2.) Use Av mode and Tv mode as necessary. Use Av mode in "questionable" light (NOT on a dark ride -- these are almost impossible for the DSLRs, let alone a little-sensor camera like the S3) and set the aperture as wide as it will go (2.7) and don't zoom too much. The camera will pick the highest possible shutter speed it can -- only raise the ISO if you can't get a fast enough shutter speed.
Use Tv mode when you MUST freeze the action and set it as high as the camera can find an aperture for (it will blink red if it cannot go wide enough).
3.) Set your MyColors to P (Positive Film) it will give your colors a "kick" but it's not so overpowering as the Vivid modes.
4.) When in low-light situations, set the camera metering to Spot and take readings (half-press the shutter button) on the bright areas of the subject. If the background is dark/underexposed it won't really matter if the subject looks good.
5.) Learn how to use the Exposure Compensation (half-press the shutter and then press the ISO to lock exposure settings -- you'll see a '*' in the EVF/LCD) this allows you to set the exposure and then recompose/focus your picture to get fewer blown highlights or underexposed dark areas. Sometimes you can get a beautiful picture by exposing for the sky and then recomposing on the buildings/people.
Good luck and have fun!!
