I don't know about free, but Paint Shop Pro, now owned by Corel http://www.corel.com/servlet/Satellite/us/en/Product/1184951547051#versionTabview=tab1&tabview=tab0 costing $80, has a drawing effect, but as shown in this example http://www.flickr.com/photos/9672970@N08/3372341169/ the appearance of the result may depend on how much editing you do along the way. The original source is in the lower left and when simply converted to gray scale and having the effect applied (at 40% detail) gives a drawing that is unsatisfactory to me - to draw it would take too much effort for the content. Previously, I had edited the source to eliminate the background and reduce the color count and that is shown upper left and the drawing produced from it with the same settings looks much better to me.
If you find free software, that gives you an example of what you need to look at.