The maker of Plan B morning-after pill is asking the FDA for permission to sell the drug without any age limits. Currently if you are 17 and older you can buy the pill OTC without a doctor's prescription. http://articles.nydailynews.com/2011-02-14/entertainment/28616131_1_regular-birth-control-pills-plan-b-morning-after-pill-teva-pharmaceutical-industries
Personally, I think younger girls should have access to it. It would prevent a lot of abortions. I don't think it would increase promiscuity because I think if you are a teenager and wanted to have sex, you'll do it regardless of having access to the morning-after pill. I don't think every teenager is going to start whoring around just because the pill is available.