tk1999,
I started temping before going off BCP so I could get in the habit of temping for when I came off. I think I started about halfway through a cycle. I don't see why you can't start temping even if you're not sure if you've O'd or not. You can also check CM and cervix positon (if you're that keen - I'm not). You may just start seeing patterns on your chart about what may be occuring - don't know how PCOS affects charting but if you want to try it; probably can't hurt for a while (unless you start obsessing too much on the charting)
Hope this helps a little
Liz