I have an invention that I do not want to patent, however I would like to go on record as being the inventor.
How can I publicly GIVE my idea to the world?
Publish a paper that fully discloses all of the details of your invention. Or, if this invention is related to the invention that you are trying to patent, just fully disclose the invention in the "background of the invention" or the spec, and don't claim it -- anything disclosed but not claimed ina a patent is dedicated to the public.
Or file a patent, get the patent granted, and dedicate the patent to the public -- but that's the expensive way!