In theory, developers should be able to do great things for non-profits. In practice, it seems hard for a developer with spare time to find a non-profit to work with. Somewhat nuts considering that the open source community has plenty of experience with all the issues of volunteering, distributed teams, etc, and there are some great teams out there - hundreds or thousands of developers willing to put in time over the long term to help advance good causes with their skills.
So treat this as a who's hiring post, more or less, but for non-profit volunteering with technical skills.
(A thought on the issues: reliability is the key, central value needed for a technical volunteer. In any non-profit, volunteers come and volunteers go, but it is very challenging to find people who follow through on a commitment to stay for a given project, or to act as support for a non-profit site for the necessary months and years to build up familiarity with the systems used. When it comes to technology, those rare few are absolutely necessary, however - you simply can't run a tight ship if developers flake out on a regular basis. This is especially true when it comes to projects wherein the team is scattered across the US or the world, and rarely meets in person).
My ulterior motive: I get to tack my search for a LAMP developer volunteer for the very hip Methuselah Foundation in here an early comment.