I have two favorite Pitas. Both are whole wheat. One is the kind that is available at Whole Foods (Western Sierra -- 2 WW points) and the other is the kind that is available at Safeway (also 2 WW points). Getting to eat a whole pita for 2 points is really great, since it is filling and seems like you get to eat a lot of bread, which is usually hard to do on a weight watchers diet (while watching points).
In terms of hummus, you can read my post about my favorite types of low calorie hummus (Sabra and Emerald Valley), their calorie content, and where to buy them by clicking here. Generally, you can buy hummus in the refrigerated section of Whole Foods, Safeway, or Trader Joes. They all taste a bit different, so you'll have to find the one you like the best. I usually try to only spread 1-2 WW points into my whole wheat pita bread for a 3-4 point lunch or snack (that is, without the cheese of course). I hope you enjoy these wonderful foods together!
By the way - pita bread is also a great "crust" if you want to make low calorie pizza at home!