There's a good essay about Mahfouz on the Nobel Prize site.
Update: I have a reflection on Mahfouz on the Guardian's Comment is Free website and was also interviewed by Radio France International's English broadcast about his significance in Egypt and the Arab world. Let me know what you think. The funny thing is that while I'm not actually a great fan of Mahfouz's work, I loved the man and his persona. If you really want to know tons of great anecdotes about him, pick up Gamal Ghitani's recent book (in Arabic only, for now) about the literary salons he held throughout his life, which Ursula wrote about here.