Heres a small tutorial to create vector images in flash.

first: get a photo, a big photo. you can enhance the colors in photoshop to see a better change in contrast

then get the line tool(N) make it a hairline and pick a color that is not in the photo, with this photo I picked green, but i could also have used blue.
draw all the lines, and use the black arrow(V) to bend them in the right shape.

when you finish the lineart, open up the color pallet and add the colors you want. i prefer to use realy light colors for skin(255 - 220), but lots of contrast in the hair. clothing is dificult, so i try to avoid using pictures with to much clothing.

now, when you think its done remove the lines. do a last check if you didn't forget to color some parts, and ALWAYS keep a backup of the colored one with the lines, just in case.

to export the file I create a new file, make it the right size and use match size and align to get it to be the full document size, then export image as PNG. you can also export it as a Illustrator file, but you have to recolor the entire thing, but you can make prints, CMYK style!

enjoy, and good luck