IBM DataPower Knowledge Center: http://www.ibm.com/support/knowledgecenter/SS9H2Y (Select the appropriate firmware version)

IBM DataPower Gateways: http://www.ibm.com/software/products/en/ibm-datapower-gateways

DataPower education training paths: http://ibm.com/training
Select “IBM training paths and certification”
Select Category: WebSphere – DataPower