And Golfdriver is being modest, since he wrote the original guide on flashing a Samsung ROM. [Samsung] How to flash Stock ROM via ODIN is the updated version, with pictures from the latest version of Odin.
don't try to download OTA updates anyways, if you want to keep your root. You never want updates from the carrier/manufacturer. You never know when they will sneak in a locked bootloader or other thing to prevent rooting/custom roms.