Whilst I wait for the files to finish uploading to my server so I can install for the first time, I thought I’d ask this question:
When version 1 comes out will we be stuck using whatever payment gateways are already integrated, or will we be able to also integrate others ourselves? I’m not sure yet which my client would prefer to use, but it may very well be one associated with one the UK banks, rather than someone like Paypal or Worldpay.
For the UK, you will only have the choice of PayPal (various methods) and Google Checkout, out of the box anyway.
If you want to use some other payment service provider (payment gateway), you will need to integrate it yourself or get someone to do it for you.
Writing a new payment module shouldn’t be too much trouble for a decent PHP programmer, but the documentation isn’t great just yet and some aspects of the APIs are in flux (but should be stable after ver 1.0).
There is a brief intro to writing a payment module here, although at the moment a couple of details are out of date:
http://www.magentocommerce.com/wiki/how-to/create-payment-method-module