Immigration: Easy and quick because flight from Apia only holds about 20 passengers. I was the only tourist on the airplane.
Customs: Also very easy because I was a tourist. Customs guys looked ready to check the locals.
Currency: American Samoa uses US currency
Electric: 110 volts
Getting into town: The airport was a ghost town when I arrived. All rental car agencies and all other offices outside the airport were closed. Most had a phone number to call if you wanted assistance. I asked a local how to get a taxi and the policeman called for one on his walkie-talkie. Taxi from the airport to Pago Pago was $15 (about a 20-25 minute ride).
Airport tax: None, it is included in the ticket price.
Airport Services: At the time of my visit all airport service were closed. This included rental car companies and gift shops. You are required to wait in the outside area near check in and curbside until after your flight has arrived.