All credit goes Angela who runs the paper rush blog http://paper-rush.blogspot.com/! I was browsing (stalking) her blog, and came across this photo
http://www.amazon.co.uk/Sticky-Index-Flags-Leather-Post-/dp/B0027DUSYG/ref=sr_1_13?ie=UTF8&qid=1307561040&sr=8-13 (I really like the look of this set) and stick them on the ruler! If they get in the way of your week view, just move the ruler. And once you've finished them, take them off. Thanks to Angela!
I'll be trying this once I switch to week-to-view for the summer!