One of the standard treatment options for prostate cancer is external beam radiation therapy. More recent radiation therapy planning methods with three-dimensional therapy or intensity modulated radiation therapy (IMRT) allow safer delivery of higher than conventional daily doses of radiation. The purpose of this study is to compare the effects (good and bad) on patients and their cancer of the standard dose of radiation therapy (41 treatments over 8 weeks) with a higher daily dose (experimental) of radiation (28 treatments over 5 and a half weeks) to see if the effects of the treatments are similar.