Two toned image - drawing?

I’ve been looking for a way to modify some of my images into a very few number of color-tones, but still looking good. You’re propably thinking, what the hell is he talking about, so I’ll drop a few links to images with the effect I’m trying to make.

Is it just the time swollowing way, by sitting down and draw it all out, or is there a faster and smarter way to do it?

http://www.vectorizedme.com/projects/Kalendar.jpg
http://www.vectorizedme.com/projects/Vektorika.jpg

Tommy_S, hope you don’t mind, love your new(???) website.

[edit] I’m talking about the effect on the girl ( 1st img. ) and the head ( 2nd img ).[/edit]