How to set up a laser-pointer communications system over very short distances
It is strongly recommended that you set up a laser communications system over a very short distance before you go out into the "field". You can use red laser pointer pen or Multi Color Laser Light to setup that laser communications system.
At these short distances it is possible for the person pointing the laser to see the distant end and the "spot" produced by the laser hitting the target. It should go without saying that being able to see the spot produced by your transmitter greatly simplifies the aiming process - and it also goes a long way toward getting the "feel" for how your equipment will work. It will also reinforce the realization that many people who go out into the field to attempt laser-pointer communications underestimate the practical difficulties involved.
The use of cell phones do have a distinctive disadvantage: Because they are digital, they have a rather obvious end-to-end delay that becomes increasingly apparent when you are trying to do "real-time" pointing. Hearing the sound of your beam going past the receive end's detector by listening to its speaker via the telephone will be slightly delayed (up to several hundred milliseconds) and this delay can make aiming awkward. Also, being digital, a tremendous amount of "lossy" audio compression causes those brief tones and background noises (such as those emanating from your optical receiver) to "confuse" the audio compression, often resulting in what you are hearing over the telephone sounding very different from what you would have heard directly from the receiver.
Even at such short distance, it also becomes very apparent how "touchy" the aiming of a laser pointer really is. One of the first things that discovered is how useless a typical photographic tripod can be as a means of aiming a laser.