Bookmarklet to save a file containing all of the subscribed other sites (child sites for a motherblog). It can only capture EITHER the "Subscribed" or "Inactive", which ever page you're currently viewing. If you want to save both lists, you must click the bookmarklet once on the subscribed page, then navigate to Inactive, and click it again.
To get the bookmarklet, you must first go here: active export page and follow the instructions.