Keep in mind too that mold can be really hard on the material it lives on. In fact, mold can seriously degrade the structural soundness of your walls, and should be repaired by a professional. Fabrics that have mold on them, but can't be placed in the washing machine should be thrown out, and all smooth materials need to be washed down thoroughly to eliminate the problem.
Once you've figured out where the moisture is coming from--and you've addressed that problem, you can go ahead and remove any existing mold. Be warned however, that experts suggest that homeowners only tackle small mold problems on their own. Anything larger than 10 square feet requires a professional.
If your problem is minor--like mold on a window sill for instance, you can remove the mold with detergent, a rag, disposable gloves, and a dust mask. The mask will protect you from inhaling mold spores, which can cause respiratory problems in sensitive people. Be sure to wipe all visible mold spores away, and throw out all the materials used in the clean-up. One caveat however, don't use bleach--even if your mother tells you to. Bleach can't get rid of all the spores, and isn't completely effective at disinfecting this type of material. It's better to use a household detergent to get rid of all the particles.
If you don't get rid of mold, what are its effects? The answer really depends on your individual sensitivity. Some people have trouble with coughs and fatigue, as well as headaches and respiratory problems. These are much more pronounced in people who are allergic to mold, and to those who have an infection (mold growing inside the body). Most of the time though, people breathe in mold particles and are fine, but there are toxic molds out there, and overexposure of any kind is bad for the body. If you think you're experiencing a mold allergy or infection, see your physician right away. M Shane