Your equipment will depend on your purpose. If you want to compete, get good quality competition gear. Get an open front IPSC legal holster, open mag carriers, etc. If you want to use the matches to practice your multiple-target shooting skills, go with good carry equipment (OWB carry holster, carry mag pouches, etc.). I shot IDPA last summer specifically to practice shooting skills. I didn't care where I placed as long as I hit my targets multiple times in short time frames. Most competitors are there for the rankings and points. As such, they use gear designed for that. It's all up to you.
Training is available, but your best bet is to go to a match and meet seasoned shooters. You'll be surprised at how many experienced shooters will volunteer tips and techniques. I'm sure you'll befriend someone fairly quickly. Good luck!
Go to a match and watch the course of fire. ask questions, I'm sure you will find many offering to help you out. years ago I got people interesting in competing by letting them borrow holsters, mags, and pouches. all they needed was their gun and ammo. get hold of one of the current rule books, contact IPSC thru USPSA (United States Pratical Shooting Association) to get hold of one. it's a lot of fun, but it's not like riding a bicycle, to get better requires practice and more practice but you will begin to see your time and score improve pretty quickly.
