I'd like to know if someone has pointers to a similar writeup but focussed on Europe rather than US. AFAIK neither Google Checkout nor Amazon Payments are available in Europe, but I'd love to be proven wrong.
You can't do a EU-wide guide easily, because you will need a merchant account at a bank in your country (and you typically can't use one from another country), and you will need a processor that can work with that bank (which will typically be a processor from the same country) and finally a provider that can work with that processor, again, mostly country-bound.
If you're in Denmark I can recommend http://epay.dk as a provider, their SSL relay solution + some AJAX allows you to make really nice payment interfaces that are completely branded and integrated, without the hassle of PCI compliance for your site.
(As processor we use http://pbs.dk, because, well, there's noone else really.)
