Hello DustinMan. I think the best way to learn is a "hands on" approch. All you would really need to now is what you can do with the control panel and how to setup/ configure domains.
Once you sign up for a resellers account, the host (should) will usually send you detailed information on "how to" do such things. What I would suggest is depending on what control panel you are thinking of using, go and try out the demos and spend some time just configuring.
Once you have your account established your host can generally provide you with a lot of information.
Most reseller hosts have online documentation and FAQ's. Their support mechanisms are available to help you out as well. Many have forums where you can post questions and generally discuss the wider world with other people.
Try reading up on the basics of the control panel you will be using and also ask around. Places like WHT are a great resource you should utilise for information. Many people here have been through what you are or will go through. Everyone has to start somewhere, and everyone was once a beginner at some point. Many people out there are more than happy to help you out.
Along that vein, your host generally will be more than willing to help you out too.