Are all cell phones 3G

no, and there are different types of 3G, one would be UMTS for GSM phones. GSM phones are the ones that take SIM cards or smartchips (same thing) the other form of 3G is EVDO which CDMA/TDMA phones can use, these phones cant take SIM Cards most carriers have phones that have 3G capibillities, and usually offer 3G service only in metropolitan areas.