I second everything that magkelly said. In my case, I have florescent and yellow lights in my living room, in different locations, so I turn all of them on. My camera also has some automatic filters that adjust for indoors lighting, so check if yours does as well. Look for one that's labeled "tungsten", it really helps to balance out the yellow of incandescent lighting. These two pictures were both taken at night, with incandescent overhead lighting, macro setting, no flash, low ISO (80 I believe...might have been 120)
with cooling filterwithout filterAlso consider rigging a ghetto light diffuser. Basically, use a white sheet, something to drape it over and pin tight, (a large cardboard box will work, and a desk lamp that has a moveable head, and point it at the diffuser.
And of course, photoshop is a godsend. Judicious use of curves, levels, noise reduction filters and color adjustments can make a world of difference. These pictures were taken with macro, no flash, on a rainy day. Incandescent light from behind the camera, about ten feet away, with cloudy daylight in the window behind the subject. Higher ISO on these pictures, something like 200 or more, hence some of the graininess, but if my indoor lighting had been closer, the ISO could have been lower.
before photoshopafter photoshopAlso remember to use an image editing program to resize your pictures, rather than letting photobucket do it for you. Their compression SUCKS. No really, it's awful.