Yahoo announced they have made the transition from Yahoo powered search results to Bing powered results in the Asian markets.
These markets include Hong Kong, Indonesia, Malaysia, Philippines, Singapore, Taiwan, Thailand and Vietnam but exclude Korea.
Yahoo also said the transition for the organic results in Greece, Poland, Romania, Switzerland (German, French and Italian languages) and Turkey are complete.
I am not sure when the paid search side will be transitions, there have been issues on that front - from what I understand.
Forum discussion at WebmasterWorld.