TexasCHLforum.com

I don't know of anyone that's teaching courses in IDPA shooting. Basically, shooting a local match IS the training. You can watch other more experienced shooters and ask all the questions you want. You'll get all the advise you ever wanted and then some.
Go to http://www.idpa.com download and read the rulebook. It spells out clearly what is required. Also, on http://www.ccidpa.com there is a good explanation of the basic equipment needed to shoot an IDPA match.
Once the rulebook has been read, just show up with what you've got and folks will loan whatever else you need to shoot.