This is going to be a TLDR because I don't have much time to type. I would second the Skywarn class -- however, know that Skywarn classes are almost useless in the field in the sense that I've seen probably half a dozen classes (usually they have them after weather conferences) and they are usually attended by HAM geeks, not chasers and consist of some slides and a guy talking. I've never met anyone at a Skywarn class that I'd feel safe making chase intercept decisions or in letting them watch the sky.
You do need to be educated, though. To do that, here are three great ways, in descending order of usefulness (and none of these preclude the others):
Go on a storm chasing tour and ask a LOT of questions. This is expensive. But If you are chasing with Cloud 9, Silver Linings, or Tempest Tours, you are literally chasing with some of the best chasers in the world who will show you what a successful intercept looks like. You can also try chasing with the College of Dupage, who treats it like a class and can actually give you college credit for the chase. If you don't have lots of money, though, this is not a realistic option. Storm tours are not cheap. (Neither is chasing, but chasing is a lot cheaper than a tour).
"I'd like to use my phone a friend..." Know a chaser? Or don't know a chaser but live near Oklahoma City? Find someone willing to take you along in exchange for splitting gas costs. This is a bit of a crapshoot, since there are lots of idiot chasers twentysomething chasers who will gladly show you how to chase like a moron. But it's probably still better than just striking out on your own with no knowledge.
Book learnin' is good learnin'. Read up on how to chase. In past years, http://www.stormtrack.org was a great resource for this. Browse back through the archives. There is a LOT of information and knowledge wrapped up in that forum. Also, read up on how supercells work and how to forecast severe weather in general. There are books that do this, but there are websites too, such as habyhints. Basically you want to know as much as you can about supercellular structure, tornadogenesis, likely tornado paths, likely hailcore locations, how to identify likely rainwrapped meso, etc, before you go out, not after. You also need to know what kinds of information you will need -- for example, what are you going to use to display radar? How are you going to manage mapping and navigation? Etc.
If you have any detailed questions, feel free to post them here and I'll try to answer them later today when I get to a place where I can type for longer. :)