I've booked off the two weeks of the main Olympics from work and I'm tentatively planning to not even be in the country for it. The remaining 4 weeks will see me cycling to work, staying firmly away from the tube and buses and probably loudly complaining about the whole fiasco!
My preps will be making sure I have food and spare clothes at work in case I get stuck in the office, finally sorting out my EDC bag and kit that I have on me at all times and researching more walking routes home in case something happens to my bike.
I've said on another thread that the website http://www.getaheadofthegames.com/ is pretty useful for seeing which tube stations are going to be particularly gnarly on particular days. Also the cycle maps from TfL are not just good for cycling, but useful for finding where the quieter roads are, which in a terrorist / riot / hell-in-a-handcart-on-the-main-roads situation could be a lifesaver.