Last night Rev. Mac Frazier gave a great talk about doubt at the Sunday Night Thing. It was part of the current series, "Feelings: What the heck? - Emotions and Spirituality." His main text was Arcana Coelestia 1820, which is a great passage about how the evil spirits attack what we love.
The exciting thing is that I finally remembered to bring my digital recorder to the service so, if you missed it, you can listen to Mac's talk online. At the Sunday Night Thing the readings are done by people in the congregation so if you're having trouble hearing those you can read along with them by clicking on the link to the Arcana Coelestia passage above.