dSLR Portraiture Woes!

So, my latest quest is to learn how to capture portraits of people with my Pentax K10D dSLR. It was so easy with the Canon S3 IS, which is a sophisticated point-and-shoot, but having to A) set the correct aperture, correct shutter speed and not introduce any motion blur using a telephoto lens makes it easier said than done. Today, I put my father's borrowed 50-200 mm zoom lens on and took some pictures of my nephew, niece and daughter with natural light only, since I still don't have a real flash, nor do I understand how to use one correctly yet. . . I set the camera at f/5.6, left it at 95 mm, and the camera took the best picture at 1/20 sec. Unfortunately, in order to be able to take blur-free (reasonably) images, I had to set the ISO at 800! Grain-city, but easily removed with denoising software. Also--I had to use Auto White Balance in order to get color approaching normal as opposed to other custom white balances. . . The picture on the bottom is Maya, climbing her loft bed ladder. On the top, she's looking surprised and this one is quite soft-focus, not my intention! Below is a version I desaturated. . .

This ----------------------------------------->

is what the images look like before I've used the noiseware and portraiture denoising and photoshop unsharp mask. 800 ISO introduces a lot of grain or noise. . .

And THIS one on the left is how good it can look with the portraiture denoising used to smooth out skintones. I like! Butterscotch pudding heaven, while on belay on the loft bed!

The Entertainer? This is my nephew, Miles, showing me how well he plays the piano. He's quite the character! I took the picture in color, but desaturated it, using Photoshop (hereafter to be known as PS, for ease of moiself!)

My niece Eve, and Maya, smiling preetty for the camera! I used the portraiture denoising on them, too, to smooth out the old skintones. . . Maya was disappointed to see that her freckles kind of faded away with that process, because she really likes them. . .

And last but not least, this headshot of Maya--my beautiful girl!