Tourism is strictly controlled by the island elders to maintain the island's culture.
Boats from Isla Amantani stop for a few hours at the island. There are also direct boats from Puno, usually part of a tour that stops at the floating islands on the way, which arrives at 11:30am and departs by 2pm. Travel time by boat from Puno is 2 hours and 30 minutes each way.
A fee of 5 soles (as of February 2010) is charged when you enter the island.
Tours can be arranged through any travel agent in Puno for around $10 US, or easily acquired at the dock in Puno before 7:30am. The boats are typically nice, with reclining seats.
The only mode of transportation on the island is on foot via steep walkways.
For a full exploration of the island you need to stay the night. If you only have a few hours climb up to the mirador north(?) of the little town. It's the highest point and gives a nice overview over the town. There is also a temple still used to bring sacrifices to Pachamama.
Locals sell textiles and other souvenirs at booths typical of this area. Bargaining is frowned upon.
On the plaza there is a community restaurant. Profit is used to help the community. There are also several other restaurants. For tour groups, the elders mandate which restaurant the group will eat at. The food is simple, typically fish from the lake, although omelets are usually available for vegetarians. Food is expensive on the island, 15 - 20 soles for a set menu that would cost 8 soles on the mainland. Food is also expensive if you stay with a family overnight.
There are about 70 families who have basic accommodation. The elders will decide which families will accommodate guests. The typical fee is $3 US, and gifts of fresh food are appreciated.
Be sure to catch the boat back to the mainland or plan on staying there overnight. Boats leave from the opposite side of the island as the dropoff point. It is possible to join a collectivo boat returning to the mainland so you don't have to pre book a ticket with an agency in Puno.