Here is a pic of an indoor photo using my current lens 15-100 Nikon. It is obviously not good for indoor, low light shooting.
The Sigma 17-50 mm lens is supposed to let in a lot of light. It is a wide to standard zoom with a fast aperture and lets in a ton of light. I ordered this lens and will let you know how well it works for me. Hopefully I will get better results than I am currently getting with my other lens.