Park your car near the Pala Lagoon and walk next to the airport fence across from Coconut Point. Walk all the way around the corner, past the 'point' of the airport and there are several areas to snorkel. The reefs, accompanied by the crashing ways all around, keep the big fish out and provide a huge area of large clear pools to snorkel in.
This is probably the best hike on the island. Park your car in Fagasa pass, you'll see a sign (park at the sign) and a dirt road that heads up to Mt Alava. Hike up the dirt road all the way up to the radio towers. The best views of Pago Pago Harbor are from here. Keep hiking up past the radio towers to the large "congregational hut". If you look carefully you'll see a steep trail that goes down the other side of the mountain past the hut. This is the best section of trail on the island and has some killer views. If you make it to the end of this trail, Vatia Bay area, take one of the buses back to your car in Fagasa Pass or hitch hike!
Every Saturday at 12 noon the yacht club meets. They have Optimist , Laser and Hobie 14 & 16 classes. It's free and you can learn how to sail in Samoa! The yacht club is across the street from the only post office on the island close to Utulei.
Head towards Poloa or the west side of the island on Highway 001. You'll pass an old boat laying in some grass on your right and there's a road next to the boat that heads up the mountain. You won't miss the boat, there's not a whole lot here. Head up the road and if you look carefully you'll see an old run down building surrounded in jungle foliage. Hike up to the building and explore. It's an old haunted girls school. There's some stairs that lead up the hill to the school, but they are pretty covered in vegitation. Make sure and bring some flash lights.
Pago Plaza is actually a large place. There is a lot of tourist stuff to buy. Prices are a little high. If you cross the street and go one block you will find small local shops with real Samoan goods. The prices are marked, and high. The people running the shops will barter with you. I bought all my gifts and the marked price was $125. After bartering I paid $30. Watch out for tourist stuff. Some things will be marked "made in India".
Make sure the tide is down and head to the blow holes in Vailoatai. You can jump in some of them and explore the under water sea caverns. There's also some snorkeling outside of the caves.