whats a good setting to have for taking pictures in an unnatural lighting situationwhen using an SLR?

Answer 1

There is no "good setting".
In reality, almost always you set the shutter and aperture for the exposure you want, and deal with the lighting situation separately.

In a digital camera, that means setting the white balance or shooting RAW, then adjusting the WB in post processing. In film, there are filters you can use, or the color can be altered during printing.

In either, you can gel the flash to match the ambient. This happens often in wedding photography, where it is important to get the dress white, the tux black, and the skin tones right in mixed lighting. A gelled flash makes everything the same color, so it can be corrected together.

I recommend a book, "Understanding Exposure", by Bryan Peterson. And it wouldn't be a bad idea to pick up a good beginner's book on photographjy as well.

Answer 2

Is it a film SLR or a digital SLR? With a film camera, white balance is contingent upon the type of film you are using or you can control the white balance by using specific filters. If it is a digital SLR you can set the white balance according to kelvin temperature, in other words you can set it to tungsten light or fluorescent light etc. Or usually there will be a custom white balance setting. To use that just point the lens at a white object and press the shutter to set the white balance.