Hi.
In Auto the camera may very likely increase the ISO setting (Film Speed). This allows the camera to use a faster shutter speed or wider aperture for lower light conditions. Unfortunately this is where digitals suffer. The higher the ISO the more sensitive the sensor needs to be and the more vulnarable it is to undesirable artifacts (Noise).
Top end pro digital SLR's are less prone to this due to their larger sensors, but digitals are just less able to handle low light conditions compared to traditional film cameras.
Using flash is probably the best option, or trying manual or semi auto (Aperture priority maybe) settings.
Bear in mind also that what the human eye adapts to and percieves as reasonably bright indoors is not what will be captured on even a traditional film camera. Indoor shots that are not lit with flash or some other form of lighting, other than domestic lighting, will rarely look very good.
Sark