An extensive preview(and interview) of the upcoming Uncharted 2: Among Thieves has been posted on Gamespot.
A quick excerpt from that:
"On the surface, it may look to the pessimistic observer as if Nathan Drake has been plucked from one exotic locale and dropped right into another. On some levels, this is true: Uncharted 2 will trade in the lush jungles of the original game for snowy Himalayan cliffs and dense Nepalese cities. "
Read the rest of the preview here.