I did! I used OPK's too, it helps to get you more in tune with your body. With BBT, you don't know you O'd until after the fact, which is why the OPK's helped.
I did--I would bet that a lot of women on here did. I thought it was really useful, and it taught me a lot about my body. You might want to tell your friend to check out fertilityfriend.com--they have charting software to use and offer a lot of great info on how to chart, what the temp shifts mean, other things to track, etc.
Re: Basal Body Temp ?