The BEST credit card transactions are offered by stores.yahoo.com, they will deposit the money directly into a US account with a minimal fee and they take care of all the back end work. All the transactions are secure, not to mention once you are a "yahoo store" people who search yahoo.com to buy things will have you come up as a listing.
*I should mention that you will have your own domain
www.*****.com or whatever and it will appear to be "non yahoo" but yahoo does all the transactions. For an example of what I am talking about head to
www.allmyhome.com (currently a business i work for).
Currently working for two e-businesses the one running off yahoo stores has required less advertising to get us business and works out to be the easiest to fill the orders. As everything on yahoo's side is done online, click and print and then ship the order.
As for shipping, go with UPS. They might be a bit more expensive but trust me if you NEVER want to deal with a lost or stolen package deal with them. All the rest out there beat your package up and I highly doubt you want people senting you papers back that are all messed up. If you are making small margins you have to do it once, and do it right. Dont waste your time with any half @ss setups and go big or go home.
Also if you run a "data base" website there is a new search engine call foogle that you should resister to increase business.
If you want more details, pm me.
Rob