Ah Texas, I may not have been born there but I got there as quick as I could.
Bad news, unfortunately, but most help desk schools are not worth the time of day or the time to participate in them. Self study does no real good for you if you don't know what to study. My suggestion for that is to cull through newspapers for help wanted adds for Help Desk Operators, build a list of most requested applications and start studying the. Oh, by the way, these applications can be very expensive, Look for a company where you meet the general requirements and apply there. Let them train you for what they want.
Most Companies, (I speak specifically speak of IBM and Lexmark) don't really like trade schools, with a few exceptions. Help Desk's are usually a entry level job. The prerequisites would usually involve the applicants ability to speak to any customer without losing tempers because they don't understand you. The knowledge of the product set that company supports. Your demeanor while you are on the phone. Your ability to translate "Engineer speak" into "People Speak", Can you play well with others?
Product sets will change between each company and sometimes within one company there will be many support desks.
When I interviewed prospective employees these are the things I looked for. I have 20+ years working support desks For IBM and 15 more years with Lexmark.