you can also try newbielink:http://www.scentair.com [nonactive]. scentair is the leading provider of scent machines for businesses. they have clients such as westin hotels, bloomingdale's, sheraton hotels, macy's and lucky brand jeans. they also provide custom scent systems for museums, theme parks and the military. they also provide a home edition of their commercial machine.
adding scent to an environment is actually a very hot concept right now in the retail and hotels business. businesses are realizing that adding scent to their currnet branding campaigns can help create a "multi-sensory" experience that is more engaging and memorable.