imi,
If you want inside the pant type of holster, look for a holster with reinforced top, one that will not collapse when you pull the gun out, one that allows you to reholster with one hand. Also the holsters should have belt loops to keep it secure in one place. The Sparks Summer Special (the original iwb) is great or any iwb holsters from Sparks if you like leather. If you prefer Kydex, check out Blade Tech.
Good luck.