Distimo, an app store analytics research company, has taken a close look at Apple's App Store growth in Asian countries. They've discovered that App Store consumption has seen lots of growth in the last six months.
Who is the fastest grower? China, their research shows. Despite having only had an official App Store since last fall, China has quickly become the second largest iPhone App Market. First is the US.
Japan brings in most of the revenue for the Asian App market. In Asia, paid to free App download ratios are much lower than in the US and Europe, which tend to be more willing to pay for Apps.
You can read some of the key findings at the Distimo blog and download their publication from their provided link.