if you are a natural forefoot runner, DO NOT deliberately change your footstrike. it is possible to do. i did it. however, it will most likely create more problems than it solves.
go to a good orthopedist, and get orthotics. it's not the shoes that's the problem, it's most likely the structure of your foot.
in response to some of the above comments, forefoot runners generally have excellent calf strength. when you strike w/ your forefoot your calf is constantly contracted. forefoot running has little to do with the strength of lower leg (or core) muscles, and more do with the natural angle at which your pelvic bone is tilted. if it's tilted forward, one is already in the forward motion (like falling over) and thus more likely to "catch" oneself by using the forefoot.