brow powder or eyeshadow?
I've used eye shadows for brow powder before (along with a brow wax for maximum staying power), but it's trickier to find a eye shadow color to use as there are so many finishes in shadow. In terms of brow powders, it's just a matte shade, there's not as much variety to try to pick between and the undertones for brow powders are made more neutral to fit with hair color.
For cool toned skin and fair, try products from Anatasia (they have two types of pencils, one has a spoolie to comb and soften color, and a powder compact with two shades) or the Benefit Brow Zing s in Light (wax, powder, mini tweezers, 2 applicators), Smashbox also has a couple of their Brow Tech sets (two powders and wax).
If you apply powder, use an angled brush that's a little stiffer, like the one from Smashbox, that way you get a precise application without warping the brush.
Color matching is difficult and they can look pretty fake unless you find the right one. Most brow powders are the same price as eyeshadow and are made to match hair tones. I hightly reccomend a ash blonde/light brown tone. Walk away from too dark or reddish tones. The same shade as your hair (real hair color, or slightly darker) is good.