There are no PAMM accounts available in the U.S. after Dodd Frank. There are only a limited number of brokers offering PAMM services to U.S. residents. However you CAN manage a PAMM account if you are a U.S. citizen. You CAN also invest in PAMM accounts no matter where you are living (including USA)
If you decide to manage other people's money it is a lot of responsibility. Make sure if you do plan to do this that you let people know of the risks they are taking if you are taking care of money that isn't yours.
It depends upon broker directly. Of a broker\s policy include providing services to the US citizens, then I guess you can be either investor or PAMM trader. And maybe it makes some difference if you are US citizen or just US resident?