My doctor told me that some people find their cycles go back to normal right after going off BC, but it can take up to 6 months for your cycles to regulate. Also, it generally takes 3 months for the lining of your uterus to get really thick and good for implantation (your uterine lining doesn't build up while on BC), which is why she advised I go off BC for 3 months before being to try to conceive. Of course, some people go off BC and get pregnant the next month, but this is generally what they find.
However, even without factoring in BC, my doctor told me it typically takes 6-9 months to conceive, depending on your age. So relax and enjoy trying, but don't stress about it happening right away!