I ran into a client yesterday who had had some work done by Steve Gray of 4Penny.net a long time ago. I was reminded again of the nice SQL work that Steve does. Make sure you drop him a line if you need SQL or reporting work related to GP. Tell him that I sent you and then call him names.
4Penny 4 SQL
Archived post from 2008. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.