http://www.blade-tech.com/Combo-Pak-Special-pr-897.html
There may be better, but this is definitely a Best Buy versus Fobus and other cheap stuff.
In addition to your Glock, holster, and magazine carrier; you will need at least three magazines, eye and ear protection, and a concealment garment. Which last need not be an expensive tackytickle vest with 37 pockets. This time of year, a jacket long enough to cover your rig is what you need. In mild weather, a BDU shirt is good, in hot weather, cut the sleeves off or completely out at the shoulder.
Practice drawing from under concealment DRYFIRE so you can do it safely in a match.
Lots of good introductory reading at:
http://caps-idpa.com/yahoo_site_admi...l.79123937.doc