Arthur Hlavaty has a recent blog posting about the Illuminatus! trilogy that's worth reading.
I like these sentences: "I met the authors, whom I liked, and I read and enjoyed later work by them. They admitted that the book was half bullshit, but they were never sure exactly which half. Me neither."
Nick Helseg-Larsen is working on an Illuminatus! annotation project, using a document on Google docs. If you'd like to help, email him as fuzzbuddy at gmail dot com.