I know my body pretty well from charting when ttc dd (following 14 months of trying and a miscarriage) and ovulation is the same each month. I have a headache on the day before I ovulate and start to feel 'bruised' and bloated. On the day I ovulate I have a period of about 4-6hrs where I get very sharp one-sided pains coupled with a stabby constipated pain around my bottom and when this eases I'm left with the bruised feeling for several more hours.
I assume that somewhere in those 4-6hrs I'm actually ovulating, hence the one-sided pain. I think it's probably different for each woman.
Some women get the pain before ovulation, some get it at the time of ovulation itself like showofhands and some get it afterwards. No way of telling which group you're in unfortunately!
Whilst I agree with Attilla about not timing sex on the one hand because of all the stress it can lead to, on the other hand you can only get pregnant at your fertile time. The best way of timing sex is to get to know your cervical fluid and to have sex when you see the fertile stuff. It's all about the sex that you have prior to ovulation, not chasing the egg afterwards - once you have actually ovulated it's almost always too late.