You may already know this by now, but it's due for release on September 18th of this year in the UK, and December 25th in Finland. So worldwide release should be somewhere around those dates =]
However, it hasn't been officially announced so it could change. Some say it might not be til early 2010.
If I find anything out about it, I'll let you know! =]

OK, the dates have now changed XD
According to link, the movie will be released September 9th =]