Also, some people swear by Remora. This is a synthetic holster which not only can be a pocket holster, but can also be used as an IWB holster with no strap or clip (well, they do have one with or without (it stays in place due to friction without). An added benefit is you can also get Remora's spare magazine holder (they also make something similar for flashlights), which is also designed to be carried in the pocket, staying secure due to friction, or worn IWB through friction.
Note that Remora is having a 40% off sale for Labor Day.
http://www.remoraholsterstore.com