Looking for retail management tutorials.

I am just trying to survive as an IT guy and rather than just knowing how a computer works I need to know how a business work. So I went looking on the Internets for howtos and wikis on retail management - the actual running of a store and I am not having much luck. Does anyone know where a guy can learn business processes - like inventory check in and pricing ordering and that sort of stuff - things I need to know to support POS systems at stores and restaurants. Thanks.