As a photographer and Photoshop user, I'd recommend getting the word out by targeting teachers of Photoshop / design / photography classes. I know the last photography class I took, the teacher probably inspired alot of the students to purchase denoising plugins (Noise Ninja or Topaz DeNoise), and he only talked about them for maybe 5 minutes. Probably not worth "I'll do it if you send me $500 first", but worth giving out some free copies. If not teachers, good idea to find out who the influencers are in your niche and target them. (Influencers =/= Google AdWords.)