There is no one place to go to learn about web hosting. You have to figure out what you want to learn, and then go learn those things.
You'll need to learn about how to run a business: basic business setup, accounting (even something as simple as a profit-and-loss statement), taxes, licensing, customer service, et cetera.
Then you need to learn web-hosting-specific challenges: managing a server, providing technical support, accepting payments online, detecting and blocking fraudulent or damaging activity, securing your server, setting up hosting plans and prices, marketing your business...and the list goes on.
Being a web host means a lot of things. You have to be a little bit of a server administrator (even if you hire someone else to admin the server(s), you should know the basics of configuring your server, even if you're using something like cPanel.) You have to be a counselor. You have to be a salesperson. You have to be a tech writer. You have to be an internet researcher. And you have to be a teacher.
Let's say that you know how to use a computer, surf the web, register a domain, and know how to build a basic site using DreamWeaver (including basic graphics creation and uploading your site). Well, that's nice. What happens when a customer asks for help configuring their email client? What happens when a customer asks if a certain Perl module is installed on your server - what do you do? And so on, and so forth. The learning literally never stops, either, since the Internet is constantly morphing (slower than it was in, say, the mid-90s...but there's still always new stuff to learn.) Your best bet, if you know how to use the web but don't really know how to be a web host, is to take a job doing tech support for another web hosting company, an ISP, or even a corporation. (Most of the large corporations have an internal helpdesk team that provides software support for specific applications, as well as generalized support.) If working tech support is something you find interesting, challenging, or fun on some level, you might have a good shot at doing a good job as a web host.
On the other hand, if you are a crackerjack marketer but dealing with software support makes you hivey, you might want to gather a group of friends who have complimentary skills and want to start a hosting company with you. That lets you be one of the decision makers without having to know everything from the start.
If you decide to work for another company providing any kind of tech support, make sure that your contract doesn't include a noncompete clause or anything else that would prevent you from starting your own hosting company. (If you're doing software support for a large corporation, it's not likely that there would be any noncompete agreement in place. However, if you go to work for an ISP, they might have something similar in place, which - depending on the wording - might cause you problems when you decide to start your own hosting business.)
Your other option would be to find a group of friends who would be your hosting clients for a year or three, while you get yourself a reseller account. Give them a good price, but *not* so good that you're operating in the red. Use them as your "test subjects" - have them give you feedback on your support, your services, et al and make adjustments based on that feedback. Then when you are ready to open your doors to the general client base, you'll have had a few years "with training wheels". You may want to do this option while you're working at least a part time job, so that you don't have the pressure of trying to make enough money to feed yourself while you're starting out.
