Jon: Birth control pills have a few indicatons such as endometriosis, regulate periods, PMS, control acne etc. if your wife is using the pills for just contraception purpose, of course using a condom can do the job. Some men do not enjoy as much if they use condoms and so their wives would need to use the pills.
The pills consists of 21 pills in a pack, with 7 pill free days( in some countries, there are 7 placebo(sugar pills)pills). The pills needs to be taken once daily. Should she miss the pills, the effectiveness of the pill may be reduced. It depends on which pill was missed. Ask the pharmacists for more information.
Another type is the emergency pills, taken only after intercourse. Hope that answers your question.