a) Learn the rules
There's nothing like getting the information from the horse's mouth. There are three typical publications most officials use to prepare for public school, recreation league, and most private school contests. They are published by the National Federation of State High School Associations ((NFHS) See BBREF's post for the link. The site is down this morning...)
NFHS Rules Book
NFHS Case Book
NFHS Official's Manual
Read the Rules Book cover to cover then read it again. Memorize the correctable errors, then memorize the rest of the book. OK, memorize is too strong a word. Be very familiar with it but memorize the correctable errors.
b)Learn body mechanics
Somewhere in the back of the rules book, there is a page showing the exact body and arm positions and movement when calling various violations and fouls. Get a Fox40 mini whistle ($5), some hearing protection, a big mirror, and a little privacy. Practice the pictures EXACTLY trying to mimic angle of arms down to finger placement. Get used to blowing the whistle one short, very LOUD "tweet" then do the arm mechanics. This is what people see - not the mental part. Practice here will keep some of the pressure off while you learn what to do on the court.
c) Learn two man mechanics
Get an idea of how two referees cover the court. The court is divided into different areas of responsibility. Each referee has his area to officiate. The official's manual does a good job explaining where you are supposed to be and what areas you have responsibility.
d) Most importantly and many will echo this idea, get on the floor! Texas has loads of basketball. Contact that association you mentioned and have them turn you on to a rec league. If you are in a metro area, your city rec department may have youth and adult leagues and may even be willing to help you get started. The most they can do is yell at you and make you feel about 2" tall but that will pass. Once you get past the initial shock of starting out, you will learn to love it as much as we do.
As for publications, I haven't seen an "Officiating for Dummies" book. Maybe MP here will get working on that for us. You can bet there will be a howler monkey on the cover!
BTW - I can't say whether the videos will help. The ones I saw several years ago would not have been of much use to a beginner.