Step 1: Create a great Instructable
OLPC has a wiki with a discussion of the content they would like to see.
They plan to judge the content by the breadth of its educational value across age ranges and cultural context, by the freeness of its license, by its size (smaller is better), and by the ease of translation (related to cultural context, language difficulty, and the elegance of any images).
Step 2: Set as free a license as you can
Change the license of your Instructable by clicking on the "Change license" link while in the edit menu.
Step 3: Add your Instructables to the OLPC Educational Group
To do this, you first need to be a member of the group. Under the Explore heading, click Groups, find the OLPC group, and click on it. Or, just click here. Once on the group, click the join button. Now, you can add any of your Instructables to the group by clicking the "Add this instructable to a group" link on the left sidebar when viewing the Instructable.
OLPC plans to do a top tier content review in September, so make sure to get your Instructables in the group by September 10th.