Gunnermike53 has already told you how to do this. If you are on your phone right now, you are in your browser and are logged into Android Central. Go to the Fascinate Rooting, ROMs, and Hacks section, scroll to the thead called [ROM][5.07.2011][ED01]Community Rom V1.3, scroll down in the first post to the link for the v1.3 rom, click on the link, file will download to the downloads folder of your phone, boot phone to recovery (CWM), scroll to install zip from sd card, power button, scroll to choose zip from sd card, power button, scroll to downloads folder, power button, scroll to Community ROM file, power button. When file is done installing, reboot phone, done. You will still have whatever modem/radio you were running until you can get to a PC to flash a different modem in ODIN, but you will be on Comm ROM.