I've just uploaded the webwork module into the contrib/webwork directory in the CVS. Here's the README file:

This directory contains a Moodle module and a collection of Perl scripts which provide an interface between Moodle and WeBWorK.

WeBWorK is a symbolic math. problem generating/grading software platform developed by Mike Gage and Arnie Pizer of the University of Rochester Mathematics Department. WeBWorK is written in Perl and runs under a variety of Unix variants, including Linux, BSD, Solaris and Mac OS X. WeBWorK is open source software which is free for use by educational institutions. It can be obtained from http://webhost.math.rochester.edu/downloadwebwork/ (registration is required). Further information about WeBWorK can be obtained at: http://webwork.math.rochester.edu/docs/docs/

This software enables you to link from Moodle to a WeBWorK problem set assignment without requiring students to reauthenticate themselves into WeBWorK. At the end of the WeBWorK session, the students' scores on the assignment are imported back into Moodle.

The webwork module and the interface scripts were written by Zbigniew Fiedorowicz and Steve Zeidner of the Department of Mathematics, The Ohio State University. They are available for use under the Gnu General Public License (GPL). While this software has been used in a number of classes at Ohio State without any significant problems, we give no warranty, express or implied, about the its quality or suitability for use.