LingPipe http://alias-i.com/lingpipe/ had an example that did this IIRC it was their newsgroup example http://alias-i.com/lingpipe/demos/tutorial/classify/read-me...., I adapted it in to running a trial classification of Danish Laws. I remember I had greater than 80% precision without fiddling with settings and for less than a days worth of work setting up, don't remember the recall but it was also pretty reasonable.