Hi!
I'm also from Aus :) Annoying that we're behind isn't it?
As i understood it, David Kelley didn't stop the show, the network did. ABC canceled a whole bunch of shows earlier this year, as they weren't doing well in the ratings. Boston Legal had never been a good performer in this regard, which is sad since it's such a brilliant and witty show. This was my understanding of what happened but there are other sources that say Kelley stopped the show. You may be interested in reading this:
manodogs.blogspot.com/2008/12/why-is-boston-legal-canc...tml
Hope this helps!