Add an "extra field" to display payment information on Order view pages

Hi!

I would like to display the payment method the customer chose on the Orders view, but so far I couldn't figure out how to add that field. I have 3 payment methods. An off-site credit card payment method (custom module), a bank transfer method and another one which means you'll pay for your order in the store personally.

Can someone help me how to do this?

Thanks!