If you have only taken one pill late, and taken the other pills on schedule, it's not a huge cause for concern. Missing multiple pills requires a backup method.
If you took the birth control pills later in the day, there is not a problem. If you actually went 24 hours or more between pills, the risk of pregnancy is higher. If you went several days without birth control pills or did not start the new pack on the correct date, the risk of pregnancy is high.
It depends on how late you took the pills and if the pill was an active/inactive pill. There is an insert that comes with every package of birth control pills that tells you what to do in case you take your pills late. I suggest you read that.
If you took your birth control pill more than 24 hours after you normally take it, continue taking the pills for the rest of the cycle, but use an alternative form of birth control, such as a condom, as well. Otherwise, you risk unplanned pregnancy.