http://blackcat.brynmawr.edu/cgi-bin/nik/swords.pl (Internet on a CD, 07/1998)
This set up helps you find words from a standard system dictionary. All you have to do is provide a pattern, placing a "_" in place of any character. For example, d___r would search for all the 5 letter words that begin with d and end with an r.
PS: Try to you use this to find the longest word in the dictionary.