About.com: Menstruation - Menstration covers the basics for young women, as well as details of what you should expect and when bleeding is excessive.
All about Menstruation - from FWHC - What really happens during those 28 days? All about ovulation, hormones, cycles, PMS, Menopause, fertility awareness, and customs and traditions of various cultures.
Comfy Cloth Pads - Advice on making and using natural alternatives to disposable menstrual pads.
The Cycles Page - A web-based application for tracking and predicting monthly menstrual periods.
KotexFits - Offers advice a woman needs about periods, menstruation, health and well being, and PMS. Includes maternity and menopause.
Lady Timer - Menstrual cycle calendar reminders for cell phones to help women track period days and most fertile days. Learn about this free service.
Menstrual Delay or Skipping - Answers to frequently asked questions about irregularities in the menstrual cycle, particularly late or skipped periods.
Menstrual Disorders - Explains the irregular menstruation cycle including abnormal menstrual bleeding and missed periods. Notes common diagnoses and treatments for menstrual disorders.
Museum of Menstruation and Women's Health - Articles, images, humor, and other resources about the cultural history of menstruation, methods of managing it, and related aspects of female health.
My Period Trends - Calculate and print out your mentruation cycle period. Set reminder via email.
MyMonthlyCycles - Online calendar for tracking menstrual and fertility cycles and symptoms. Includes a period prediction calculator and menstruation charts.
Periodic Table - Information and links about menstruation, patterns and commercial sources for reusable cloth sanitary pads and internal cups, and menstrual extraction.
Ruth's Page - Tampons - what you don't know could hurt you.
The Sacred Cycle - A powerful and transformational work which addresses what it is to be female. It empowers women by embracing the biological cycle and dispels the negative programming women receive from society.
The TLounge - A place where young women can find answers about menstruation.