From webmd: (note the highlighted info)

HPV Vaccines and Human Papillomavirus
"HPV vaccines protect against a very common sexually transmitted virus called HPV or humanpapillomavirus. HPV infects at least 50% of sexually active people at some point in their lives. The virus often clears on its own. If it persists, it can lead to cervical and other cancers and to genital warts.

One HPV vaccine, Gardasil, was licensed for use by the FDA in 2006. Another, Cervarix, is expected on the market soon.

Like all vaccines, these HPV vaccines are not foolproof. They do not protect against all of the 100-plus types of HPV. But both vaccines are nearly 100% effective in preventing disease caused by high-risk strains of HPV -- HPV 16 and 18 -- which together account for 70% of all cervical cancers, as well as many cancers of the vagina and vulva.

First HPV Vaccine on the Market: Gardasil
Gardasil, the HPV vaccine made by Merck & Co., was licensed for use in June 2006. It targets four types of HPV: 6, 11, 16 and 18. Types 16 and 18 lead to cervical cancer. HPV 6 and HPV 11 cause about 90% of genital warts.

The vaccine contains a virus-like particle but not the actual virus. Three doses are given over six months.

The cost is $120 per dose. Insurance coverage is common within the recommended age ranges. The federal Vaccines for Children Program covers the vaccine for those under age 19 who qualify. No serious HPV vaccine side effects have been found. Sometimes soreness occurs at the injection site.

Who Should Get Gardasil?
The vaccine should be given to girls at ages 11 to 12, according to recommendations from the American Academy of Pediatrics and the CDC. The vaccine is best given at a young age, before sexual activity begins and before exposure to HPV.

The recommendations note that girls as young as 9 can get the vaccine, and females up to age 26 who didn’t get it as youngsters. The vaccine is also being studied in older women.

The jury is still out on whether the vaccine is effective in boys. More research needs to be done. Scientists don’t yet know if an HPV vaccine will protect boys from genital warts or if the vaccine can prevent boys from transmitting HPV to female partners.

In the Wings: Cervarix
Another HPV vaccine, Cervarix, is under FDA review. In studies, this vaccine, like Gardasil, protected against types 16 and 18, which cause 70% of cervical cancers. Cervarix also protects against HPV types 31 and 45, which also cause cervical cancer, according to the manufacturer, GlaxoSmithKline.

Three doses are given over six months.

Long-Term Protection, Not Cure
The vaccines are not an HPV cure. But both vaccines have been shown to provide protection for five years, according to research presented at the 2007 annual meeting of the American Association for Cancer Research. New research also suggests that Gardasil, like Cervarix, also protects against HPV types 45 and 31, which account for about 10% of cervical cancers.

HPV vaccination doesn't mean women can skip their Pap tests. Neither vaccine protects against all the types of HPV that cause cervical cancer. So women still need to schedule Pap tests."