Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Over here in The Netherlands* there is also a huge shortage. Waiting times go up to two months! Shortly after the 3Gs launch in June the 'waiting period' (or however it is called) went up to one month, now up to two months.

* for those who don't know: you can find NL in western-europe, next to Germany, the UK and Belgium
 
What I do know is that some of the newer built handsets have a green sticker on them, indicating that minor hardware changes have been made.

This however, does not affect the current stock status.

The green sticker means it has the fixed power supply in it. Look at your charger it should have a green sticker too.

http://www.apple.com/support/usbadapter/exchangeprogram/

It has NOTHING to do with the 3GS itself. The green sticker just carried over to show its the new ones. All 3GS boxes should have the sticker. If not it fell off.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.