Years ago, I posted a short guide to illustrating insect genitalia in Inkscape. Now in the shadow of my dissertation writing, I've managed somehow to write a more complete booklet version.
It's free, just like Inkscape! I take you through my line drawing process step by step, from importing sketches, to laying down and modifying lines, to making special structures like setae, to finishing and exporting. I also include some more experimental techniques which may be of interest to other sorts of Inkscape users. Enjoy!
Download link: Using Inkscape for Biological Illustration (PDF)