i currently have cingular/at&t and have used their international plan for years. it is not unlimited. i wish! i've gotten killed on bills ending up over $1k with international. you basically pay $5-10/month for discounted rates, but those rates are still higher than most prepaid phone cards. i do think they have an unlimited canada plan but i don't really consider that to be international so unless that is what you are looking for, unlimited doesn't exist.