Heather5 is right. It can take up to a year for your cycles to adjust after birth control and to become pregnant. Doesn't mean it will take an entire year, but it is normal. You can use ovulation predictor kits to help you know your most fertile days and so you know that you are trying on your best days.
Good Luck!
My dr told me to not even try to get pregnant for the first two months after getting off birth control because it takes that long for your hormones to get back to normal and for cycles to regulate. I waited the 2 months and then got pregnant the first try on the third month. It can take longer though when you are trying, six months is not uncommon.
Since it's only been a couple of months since you stopped taking the pill, I wouldn't be too worried about it. It can take a normal, healthy couple up to a year to conceive, so two months is really not that long. Keep trying and hopefully you'll get a positive pregnancy test soon!
(FYI: They usually say to see your doctor if you've been trying for a year with no success...or six months if you're over 35)
Best of luck!