hi all
as the other guys recommended..FCOMs..the flt deck and sys briefings and the airbusdriver.net..for later on you can go to
www.wingfiles.com and download a heap of books in PDF format especially the geeting-to-grips series..e.g getting-to-grips with aircraft performance..etc also the operational liaison meetings wich contain a lot of useful informations
but as an ex-a320 type myself..my recommendation is to keep it simple at first and don't overload on informations and concentrate on your FCOMs
GOOD LUCK