If you use photoshop CS2 (I don't know about earlier versions) it can be done from Adobe Bridge direct from the RAW files.
Just select the files that you want in Bridge, (can be a mix of RAW, PSD, JPG etc) then Tools > Photoshop > Contact Sheet II (II sugests there may have been Contact Sheet 1 in earlier versions of photoshop) and you get a dialog box that enables you to select output page size & resolution, number of images down & across, rotate to fit or not, file name as caption etc and then hit go. I did just that at the weekend to produce 3 pages of 25 thumbnails from 75 RAW files (although it did take a loooooooog time with my poor 1Ghz processor
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