If one takes chlomid on day three of period when would one ovulate?  usual time or earlier?  

Around day 14. If you start a five day course of Clomid (clomiphene) on day three then ovulation should occur around day 14. You can buy a home ovulation kit at any pharmacy to help time intercourse. Good luck.
Varies. There is no rule; I've seen ealier, later, and the same. As a very rough generalization when cycles are not regular, Clomid (clomiphene) tends to push ovulation more toward the normal mid-cycle.