I went off of BCP's in the end of August and started temping and charting right away, according to FF I O'd that first cycle but my period came about a week early. Since then I have had anywhere from a 22 to 31 days cycles, most of which FF also confirmed ovulation. Needless to say I am not BFP yet, and this cycle is already longer then my last one, so I don't know that I am regulated yet.
Good luck to you, just remember, everyone is different, some people have been lucky enough to get BFP right off of BCP's.