Does anyone know of any good PHP/MySQL packages that assist with online shopping cart and credit card processing?

For an ecommerce site I am working on (small to medium size business), I need to employ the ability for customers/clients to be able to log into their account, much like any ecommerce/shopping site, and view current orders, previous orders, shipping dates, etc.

This seems like a lot, but in reality, it comes down to two things (the rest is just development):

• Online credit card processing (without the use of third–party apps, such as PayPal)
• Secure, web based account management – preferably NOT via HTTP, such as phpMyAdmin. I’d rather have a log in form that is part of the web page, and not a "password protected directory," of sorts. (Sorry if that is unclear. I’m partially misinformed, myself)

I’m looking for something simple, and light–weight. I can do all the backend database work, as well as the PHP, but I need a resource or package that either explains how to do it, or provides some sample source code.