Authorities in New Zealand have issued an alert for White Island. After a fairly sizable earthquake (M=5.4) near the island, the state agency that oversees volcanoes (GNS Science) is warning people to stay away from White Island for the next 48-72 hours on fears it might erupt. Normally, just because there is an earthquake near a volcano you don't instantly jump to the idea that it will erupt, but the 5.4 and subsequent earthquakes have been both near White Island and shallow (5-km depth), indicating it could very well be related to magma moving under the system.
White Island itself is a small, uninhabited island 50 km north of the North Island of New Zealand in the Bay of Plenty. It is the top of submarine volcano and is one of the more active volcanoes in New Zealand. It can typically be seen steaming away but its last real eruption was in 2001. Most of the eruptions in the recent past have been explosive, with lots of interactions with water (phreatic and phreatomagmatic). Ash has reached as far inland as Rotorua (in the recent past). There is also a nice live webcam and seismic record online.
White Island is also a privately owned volcano (well, island) because of its mineral resources as it was mined for sulfur. However, now it is a scenic reserve that can be visited by special tours. It also has the unique distinction of degassing vast amounts of gold and other precious metals in its steam (if only there was an effective way to extract them) along with a highly acidic crater lake.