Walker Metalsmiths (Ring Size Conversion Chart)
>> http://www.celtarts.com/ring_size.htm#gauge

OnlineConversion.com (Ring Size Conversion)
>> automatically convert your ring size into the ring sizes used in different standards
>> http://www.onlineconversion.com/ring_size.htm

Amazon.com (Article about finding the appropriate size)
>> http://images.amazon.com/media/i3d/01/ring-size-finder.pdf

Ring Sizer
>> You can use the sizer to find out your ring size
>> http://www.balfour.com/college/custcare/rings/img/RingSizerChart.pdf