Hi
I'm in the same boat as the first poster, I work full time (lecturer) and I'm doing my PhD viva in a few days. I submitted in August 2007 and had a mock from hell a week before which demonstrated while I was brilliant at finding typos and reconstructing sentances I'd forgotton most of the details of my PhD.
I've spent since then doing thesis read thoughs and writing crib sheets, checking for any holes and looking for things I've misunderstood or misinterperated. I've made alot of progress since the mock and probably understand significantly more about some of the background material than I did when I subimitted the thesis. I only work on the PhD one day a week, normally I use the weekends to sleep (I do a 2 hour commute to work).