Here is a 8-class lesson plan & curriculum by Máirín Duffy for teaching the basics of Inkscape to primary school children. (the class was specifically designed for teaching a US 7th grade class.) The course is themed around the students creating a logo for their fake rock band, and then creating different items based on that logo, such as posters and t-shirts.Each of the 8 lessons has a bunch of resources to run the class, including lesson plans, student handouts and exercise sheets to print out and give to the students during the lesson.
All the resources and course outline is available on this page. Máirín has already tested and run this class on a class of 7th graders, and blogged about the progress of each day — well worth a read too if you want to see how well this class performs in real life.
Even though this class is aimed at 7th graders, following along the course is also a great introduction to the basics of Inkscape for kids of all ages.