IThe new, longer 90 second iTunes music previews seem to be finally rolling out internationally. They aren't available on all songs yet, and it seems hit in miss in my testing in the Canadian iTunes Store, so whether you'll get them or not, but at least some songs are going the full 90 seconds.
After a November 2010 notification to record labels Apple originally switched to 90 second previews in the US back in December of last year. Why it took that email so long to reach beyond American borders is unknown, as is how long it will take to fully roll out now that it has begun.
In an effort to crowd source this, let us know if you're seeing the 90 second previews, what country you're in, and whether or not the 90 second previews are everywhere or just on a few songs.