What is your price range and are you willing to use flash?.
If you do not want to use flash then you should look at a fast prime lens..
Examples are the Sigma 30mm f1.4, Canon 50mm f1.4, Canon 85mm f1.8, Canon 100mm f2. All are excellent for natural indoor lighting and provide very shallow DOF..
Other options may include Tamron 17-50mm f2.8, Sigma 18-50mm f2.8, Canon 17-5mm f2.8 IS..
If you are content using an external flash most lenses will do the quality will vary with the lens and learning proper flash technique will make a big difference in the quality of the pictures..
I've never heard of a 24-75mm lens for a Canon. Are you sure?.
There seems to be a common belief that cameras can take good pictures of moving children indoors..
Well, maybe, but it depends on the house design, how big the windows are, which way the windows face, what color the walls are, and the time of day..
Plus how big the kids are..
There's a lot to be said for a flash unit and a flash diffuser. My favorite (on an XT, incidentally) is a Gary Fong Lightsphere connected to a 580EX flash..
The cheapest way to learn a lot more about indoor photography is to buy a Canon 50mm f1.8 lens, which works pretty well is reasonably low light, while standing back a fair distance, and the lens does not cost much..
Use that with your current lens and the built in flash, and perhaps a little tripod like the Velbon 343, and you'll have lots of good equipment to get you started..
There's a lot to be said for a flash unit and a flash diffuser. Myfavorite (on an XT, incidentally) is a Gary Fong Lightsphereconnected to a 580EX flash..
Yep. The best lens for kids indoors is a flash and the know-how to use it...
If I am understanding you correctly you have an XT with an external flash and a 24-70 2.8 lens (I do not know of any 24-75), you already have a great kit! perhaps add a 50 1.4 about $300 or less~ and you are all set. Or perhaps I have misread your post..
The craftsman who wishes to do his work well must first sharpen his tools.... Confucius..
Thank you so much for your replies..
The camera is in the mail and on it's way. She told me that was the lens that came with it so I'll have to look at it when I get it. If you've never heard of it she must have typed it wrong..
Thank you for the comments on learning how to use the flash. I'll need to read up on that more and try different things out until I feel comfortable with it. I know with the S2 IS I'm notorious for bad pics with white faces because of too much flash. So I have a lot to learn! .
I'm a complete beginner and I know I have a million things to learn. I'm so excited to get into the world of DSLR and I can tell it's going to become an addiction!.
Thanks again for helping me...
I'll second the theme you're getting in the replies here..
Flash is your friend - or can be made to be with some practice .
Having said that, the pop-up flash built into the top of the Rebel XT is not going to give you the results you want. You'll need to look into getting one of the Canon SpeedLite series flashes (or a 3rd party equivilent)..
This acomplishes a couple two key things: It gives you the ability to bounce the flash off of the ceiling (or a wall), and it provides more flash power. Once you get used to a full featured flash, you'll wonder how you ever took an indoor shot without one...