Roms are not specific to Sprint or any other carrier. They're phone specific, so any rom for the Optimus S will do. Read all the stickies at the top of the Rooting/Rom section so you know what NOT TO DO. Depending on what version your radio is will narrow down the roms you have available to you. If the radio is ZVH, you can choose yourMomROM, optiROM, or gROM. If it's ZVD, pick either Reborn, sROM, or Kravens CM7.