If you use your font in Flash, the font is smoothed by Flash (see figure 1). Small fonts become illegible in this case.
The way to solve this problem is to use "pixel fonts". "Pixel fonts" are not an usual fonts, and it's unable to find them among standard fonts. So you can search for free or commercial pixel fonts. But the better way is using PixFont.
Using PixFont, you just select font which you want to convert, and then PixFont generate pixel font exactly what you need.