I'm no real help for top down socks, but...If you work your socks toe up on magic loop in sock yarn... you can cast on 10-12 sts using a figure 8 cast on. work an increase at each end on both front and back of the sock until the knitted piece fits over your toes. (My socks come out to about 56-58 sts at this point, YMMV) Work even in the round until it fits to where your foot meets your leg at the instep with your foot flexed, then work a short row heel on the back.I use this one: http://www.youtube.com/watch?v=zu5YAKsAEpY
) Work in the round again until your sock is as tall as you want it to be, and finish off with about 1 1/2 inch of ribbing(or however much you like). Voila, one super simple stockinette sock. Using self striping sock yarn helps me match sock size while making these.
Hope this helps, and have fun!