Barbs play a tremendous role in how effective a hook is at bringing in a fish. Barbs are the pointy edges that are located near the end of a hook. The barb's purpose is simple; it is supposed to keep the fish on the hook. Once the hook has gone through a surface, such as a fish's mouth, the barb's purpose is to keep it from sliding back out again. In a sense, the barb acts as a barrier that keeps the fish from getting off. However, in many cases fisherman use barbs and then release the fish. This will often cause harm to the fish and maybe even cause it to die. In many species of fish, such as the trout, barbed treble hooks will tear up the fish's mouth. This is fine if you plan on eating the fish, but if you plan on releasing fish when you go trout fishing, then you may have messed the fish up beyond repair. When fishing, it is important to think about others and the conservation aspects of the sport itself. If you want to leave trout for other people to catch, then it is important that you use barbless hooks. If not, then many of the fish that you hook and release will die. I do not know about you, but that sounds like a pretty selfish way to go about fishing. So rather than going out and purchasing barbless hooks, all you have to do is remove the barbs.
One way to do this is to simply take a pair of pliers and clamp the barb down so that it is no longer extending away from the hooks frame. Most places consider bending the barb down acceptable, however, some do not. This is why it is a good idea to check with locals or DNR officers in order to make sure you are covered. Also, many streams require you to use a single barbless hook. To do this, simply use the distal part of the pliers to cut the other hooks off of a treble hook lure.
If it is not okay to make a treble hook barbless, then all you have to do is go to your local sporting goods store and pick up a pack of barbless hooks. If you are looking for barbless hooked lures, then you are out of luck because I do not think that they exist. For these lures, you will have to make them barbless by bending the barb down.