I use the stands you can get from Battlefront for their Flames of War Vietnam helicopters
http://www.flamesofwar.com/hobby.aspx?art_id=2533I find if the model is not too heavy, just gluing a rare earth magnet at the centre of mass on the bottom is enough to hold without having to bother to try and make a hole for the magnet (and since it is the bottom, it is not easily seen)