Women are at greater risk contracting it because they are infected internally. The most obvious way is to use protection such as Condoms. Limiting the number of sexual partners greatly will reduce the risk of contracting Chlamydia. If you do have Chlamydia, it is best to tell your partner so that others don't get it, or you yourself don't get it again after you've been treated. A Pap smear is NOT for detecting Chlamydia.
Treatment includes antibiotics.
Penicillin does NOT work. Rather, erythromycin, azithromycin and ofloxocin are used widely. Treatment for newborns usually runs a course of 10-14 days but relapses do occur. Once again, if you have any questions and would like to find out more, please do not hesitate to contact your physician.