2001.01.08 18:29 "Re: Transparent TIFF", by Stephane Mbaye
few software supports the transparency while importing TIFF rasters. The best way I have found to maximize the transparency recogintion is to use the alpha-channel of TIFF. This works in many Geographic Information Systems (GIS) as MapInfo or ERDAS Imagine. I don't really know how to set the alpha-channel using Photoshop under Windows environment but it should be possible. Check TIFF or Photoshop manuals for additional information.
I hope that will help you for your work.