If it was me I'd probably be trying to work out how those urls got into google in the first place.

The only real solution to duplicate content is for google to stop penalising people for their crap algorithm ;)

¥

Have no idea how all those urls got there - I guess Google just spidered my web site and picked them up.

I am working on a sitemap, hoping that will resolve the issue.

Try to add rewrite rules, so url will look the same.

As i've seen in the cvs logs, this will be solved in the 2.5 version.