For those who are totally clueless about the various birth positions one can adopt for labour and birthing, you may wish to check out Transition to Parenthood and click on Pregnancy, Birth and Newborn Care.
It is a fairly basic website that describes the various stages of labour with graphics on the various labour and birth positions. Direct link to the positions is found HERE.
Please note that I have not gone through the entire website, just the labour and birth section. And I think it is helpful to read it since it offers an overview of labour and delivery for many moms who are not even aware that they can birth in any other positions.