Easily - but wait until later, because if you let a plant form seedpods, it'll stop producing flowers.

Wait until the flowers start to fizzle out, then leave some seedpods on the plants. They'll go brown, and then you just cut them off and 'shell' them. The brown seeds need to be stored in a paper bag in a cool place until you're ready to plant them.

Don't cut off the pods until they are brown, as green pods aren't ripe.