Well, you could take the IR filter out of a old webcam. You can open DX lasers by putting the silver cap where the beam comes out of into a vice grip (Put some blocks of wood around it if you don't want to scratch the end), and pull slowly while twisting. I do not know where/how you would put the IR filter in, though.
This page has some good reading about newwish lasers (The kind dx sells, fake or not).