Firstly, thanks to all for posting.
Up front: not every post on this forum needs to deal with openSUSE. I posted here because I thought I might get some intelligent responses, which is exactly what I received. Thanks again.
I was deliberately vague concerning my “skillset” since I believe that any attempt to describe it would most likely be inaccurate or incomplete. I merely threw the thing about being a CS student out there to (hopefully) intone that I have a pretty decent idea about how computers and software work.
Let’s use the domain issue as an example. I know what a domain name is. I know what a TLD is. I know why domain names are used, and I can calculate subnets and convert to and from binary with no problem. I know what a domain name server is, and how a client communicates with it to receive the necessary information to contact a web server. I know that an organization needs to contact someone to register a domain for them so that they can have people easily access their website.
What I don’t know is: who are the good providers? How much can I expect them to provide in the way of software (mySQL, php, “storefront” software, etc.). In other words, I know what these things are, and I am confident that I can work with them, but I have no experience in the matter, so I thought I would garner some opinions.
I have written projects in C++, Java, and Assembly. I am slated to take a Database Management class in the fall (amongst others). While I am confident, I do not take it lightly, or I wouldn’t have solicited advice. 
I have done some websites before, but nothing too heavy. I know what css is, html, xhtml, etc. I just needed some pointers on the setup. I did some searching after posting to get some more info, and I gleaned some from yahoo’s small business section.
I will check out osCommerce. Also, I did not know that I had to get the ssl certificate on my own; can you expand on that?
Concerning the payment portal, taxes, etc.–I might have more questions later, but the friend I am doing this for already has a business and has been selling for a few years, so I am guessing that she has something set up for credit cards, but I will definitely be asking.
Thanks again for the responses. Keep 'em coming if you will, especially about the ssl…