I have iPhone 4GS. Some inside pics come out yellow at night others don't. Why?

BTW, I hate using flash b/c it creates major red eye and I can't always edit!

Try and change your lighting for better pictures. Move a lamp or light source until your yellow is gone.

The yellow cast is caused the the much warmer incandescent light you find indoors.

I a standard camera, we use the white balance settings to place the white balance to incandescent when shooting indoors or when using high output incandescent lamps like those used when shooting video (500 watt or 750 watt lamps)

Most cameras do alright when the white balance is set to auto, but in this setting, the shutter lag can increase while the camera tries to "read" the colour temperature of the scene, so manually telling your camera that you are shooting in incandescent light is usually the way to avoid this problem

Now all you have to do is figure out if the iPhone has a white balance configuration or an app that will allow you to set white balance on your phone

NOTE: When shooting in fluorescent lighting, the image will appear green, so again the white balance needs to be manually set for fluorescent Remember to set the cameras white balance when you intent do shoot outdoors during the day.