Paypal has a service called Website Payments Pro. I used it on a past venture and it was great. It was cheap to setup and maintain. It is a transparent solutio

Paypal has a service called Website Payments Pro. I used it on a past venture and it was great. It was cheap to setup and maintain. It is a transparent solution too, so you don't redirect users to the Paypal site unless they are paying by Paypal. Credit card payments are done from your site via a webservice.