So I found my thermometer last night-- it was with the kids' thermometers. Maybe I put it there, or maybe my son did, I've got no clue. Anyway, this morning's temp was around where I expected it to be.
I have to say, this method doesn't make me terribly nervous, probably because we used it successfully to avoid for 6 months. It seems like a good thing to me! I plan to buy my daughter a thermometer and a book when she starts to menstruate, just so she can get comfortable with knowing her fertility signals early on. The way I see it, if she's doing it from the time she's eleven or so, by the time she actually needs it she'll be somewhat proficient.