According to a report at MacNN, Apple Stores in Hong Kong are now selling the unlocked iPhone 3G in Hong Kong.
Though there were no prior announcements (unlike apple) but the 8GB model is announced for 5,400 HKD and 16GB model is announced for 6,200 HKD
The Hong Kong online store mentions:
iPhone 3G purchased at the Apple Online Store can be activated with any wireless carrier. Simply insert the SIM from your current phone into iPhone 3G and connect to iTunes 8 to complete activation
Maybe this is a surprise which Apple planned for Hong Kong citizens or just a mischievous act done by an employee. So, let's just wait for the official announcement.