• The best source for shiurim on line, in my view, is YUTorah.org
   
• Nishmat - The Jerusalem Center for Advanced Jewish Study for Women, offers an excellent information service provided by yoatzot halacha at. www.yoatzot.org.  Among the topics the site covers are infertility, spotting and vestos.  It is worth perusing.
   
• Click here for a PDF file with biographical information on Gedolim of the past millenium
   
• Torahsoftware.org has a Vesses calculator that you can download from here