ISO rating in Digital Camera?

What is ISO rating in Digital Camera? Higher is better? i got 1 KonicaMinolta 5.0MP DC, but can shoot a good pic in night time,even i have on the flash or already turn to night mode. What spec that affect this thing? For Video, when i copy to computer, found that the sound quality really bad. What points i need to care of if i plan to buy a new DC that won't face with these same problem? i planned to buy 6.0MP DC soon. Any comment for Kodak Easyshare V610? and Panasonic Lumix DMC-FX3? Or Nikon Coolpix S5? or other suggestion? but please consider the price should be like the modal i mention above. limited budget :P
thanks

ISO is a setting for how much the sensor in your camera amplifies light. Just because a camera has a higher ISO setting, doesn't mean you should use it, however. Amplifying the light your camera takes in to get a brighter image introduces noise into your picture. Too much noise and the picture will look grainy. The advantage of a higher ISO setting is that the camera can use a faster shutter speed and smaller aperture settings to take pictures. This is important when you want to take pictures of moving objects or take pictures in low light.

Typically, only expensive digital SLR cameras are able to use higher ISO settings without introducing too much noise into the picture. A handful of the more expensive fixed lens digital cameras can use moderately higher ISO settings without too many problems. Any camera in the $200 to $300 range probably won't be very good at higher ISO settings even if they are available. For low light photography, a better solution is to buy a camera with image stabilization and/to use a tripod.

Having a higher ISO AVAILABLE is generally considered a good thing, but it is NOT generally better to plan on using it for all of your pictures. That makes perfect sense, I know. Think of a higher ISO as your "reserve tank" to use in case you are running out of light and still want to get a picture. Note that I said "A PICTURE" and not "THE picture." Higher ISO are usually associated with digital "noise" or fuzz that makes the picture somewhat less desirable in quality.

Sorry, but there is too much garble in your question to give you much in the way of an answer. I've seen digital cameras with ISO ratings as high as 1600, but the noise at that level is very high. ISO rating and noise are related -- the higher the ISO, the higher the noise. The question becomes, "Which camera has a high ISO rating but low noise?"

I have a Canon PowerShot A700 and it does decent video with acceptable sound. I also have a Konica-Minolta A2 and it has decent sound and video, too. I don't know how to advise you for your video/sound question, except to say that some cameras out there do a decent job.

I can recommend the Canon PowerShot A700. It is a 6MP camera with a 6x zoom lens, and it takes decent pictures. Not the best but pretty good.

ISO stands for International standards organisation & is the means by which film (as in negative & slide) is rated for light sensitivity. A quick way to think of it is the higher the iso rating (e.g. iso100. iso400 etc) the more sensitive to light, therefore the less light you need to produce an acceptable image. You must also understand that the higher the iso the more the photo degrades because greater resourse are needed to produce an image. The "standard" is based on iso 100 and is what I personally use 95% of the time

ISO rating are for the film you use in the camera. For digital cameras it is available from 100 to 400 ISO. If you buy a digital camera with 6 mega pixels and shoot a picture in 6mp and 400 ISO, and take a printer it will look very good. But to watch all that you have shot on a computer screen you need not set your camera in ISO 400 or 6MP. Even a 3MP with ISO100 or 200 will look better in a computer screen. You should go to a camera shop and compare cameras within your budget and decide to buy the one that suits you well.