I bought a couple of books on Magento extension development and understood the mechanism on how to create a new shipping module. However in my current project I need to allow the customer to enter his/her own shipping account number and the number should appear in the order details (similar to a tracking number).
In other words, during checkout the customer should see: Shipping Method Customer Shipping Account Carrier [dropdown list to choose UPS, FedEx and Others] Account Number [free text]
Where should I start looking for documentation on how this can be implemented? Sorry I am very new to magento development.