Planned Parenthood provides the details on diaphragms, caps, and shields. (
http://www.plannedparenthood.org/pp2/portal/medicalinfo/birthcontrol/pub-diaphragms-cervi...
)
The teen sexual health section of the the Kid's Health web site provides this rundown on spermicides. (
http://kidshealth.org/teen/sexual_health/contraception/contraception_spermicide.html
)
Fertility, a British organization devoted to natural family planning, provides lots of detail, including charts, about fertility awareness methods. (
http://www.fertilityuk.org/
)