Actually, I don't beleive any make/model of cellular phone can be cloned directly from the handset except for Okis that have mod chips.
True, you could change the phone number to whatever you want, for Nokias the codes are *#639# to reprogram the MIN, but you cannot change the ESN without an eeprom burner. The MIN/ESN pair needs to match in order for a phone to work as a clone.