Matt Leventi has created a WeBWorK question type that can be used in Moodle quizzes and lessons. This allows you to use all of the features of the Moodle CMS and in addition you can ask any WeBWorK questions from the Moodle quiz/homework modules.
We are using this feature this semester at a few courses at the University of Rochester.
More information and a sample can be found at http://question2.webwork.rochester.edu.