Syzygy - 8:15 am on May 27, 2010 (gmt 0)
Journalism.co.uk used to be a good resource. I've taken on writers from there in the past. Looks bit of a mess now, but could be worth a look. They have a database of freelancers for hire...
There's also the National Union of Journalists database I've also used this in times past to seek and commission writers.