Birth Control Pills provide protection against pregnancy but women still need to use condoms as well.

Provided that the pills are taken correctly (about the same time of day, every day, without missing any pills), the birth control pill will provide very good protection against pregnancy.  The failure rate of the birth control pill is about 1% per year if taken correctly.  This means that 1 woman out of every 100 taking the pill for one year will become pregnant.  Compare this to women not using birth control, where 80-85 out of 100 will become pregnant during the same time period. 

The condom is beneficial for two reasons.  Number one, it protects you from some sexually transmitted infections (STI), like chlamydia, gonorrhea, hepatitis and HIV.  Secondly, it also adds to the pregnancy protection of the pill.  Sometimes people can have an STI and not know it, so it is recommended to always use a condom for infection protection, even if you use another method of birth control.  You should continue to use condoms until you are assured that both you and your partner are found to be negative for STIs (through testing, not just by your partner's "word"), and that you are only engaged in intercourse with each other (no other partners).  (reprinted from