Here's something surprising I didn't know:
"Climate change is expected to cause sea levels to rise -- at least in some parts of the world. Elsewhere, the level of the ocean will actually fall."
This is explained simply, but at length, in this article: http://www.spiegel.de/international/world/0,1518,732303,00.html#ref=nlint
Basically, it's a gravity effect. If Greenland loses all that ice, it also loses mass -- so it has less gravitational attraction for the ocean around it.