PCI Compliance
Visa requirements (merchant levels defined):
http://usa.visa.com/merchants/risk_management/cisp_merchants.html
Mastercard requirements (merchant levels defined):
http://www.mastercard.com/us/sdp/merchants/merchant_levels.html
PCI Security Standards Council:
https://www.pcisecuritystandards.org/
PCI DSS Requirements:
https://www.pcisecuritystandards.org/security_standards/download.html?id=pci_dss_v1-2.pdf
PCI DSS Questionnaire:
https://www.pcisecuritystandards.org/docs/pci_saq_d.doc
Navigating DSS:
https://www.pcisecuritystandards.org/pdfs/pci_dss_saq_navigating_dss.pdf
Fill out the questionnaire and show your organization how out of compliance they are.