Derek Stanton , Jul 09, 2003; 12:24 a.m.
If you have an 'assistant,' makeup artist, friend (anyone?) standing by, have him/her use a piece of foamcore to fan the model's hair. It's a two-dollar solution, but it's quite effective, as you can really direct the airflow and you don't freeze your sitter. You just have to get the timing down, and make sure the foamcore doesn't intrude into the frame.
(example: http://www.photo.net/photodb/image- display?photo_id=919590&size=md)