1997.03.04 20:09 "Re: Tiff to Fits (et al.) converters", by George Sazaklis
You can also try ImageMagick. Their convert program does wonders on converting any to any image formats.
You have to compile with the tiff library however, to get any functionality on tiff images. I presume that won't be a problem.
You can streamline the conversion as convert takes its argument filenames from the command line.
You can get ImageMagick from http://www.wizards.dupont.com/cristy/ImageMagick.html and see the man page on convert. FITS is there!