The problem with a spam word list is that you will have to constantly keep updating it and staying on top of the current trends. It's better to use something like a SpamAssassin server to do the processing for you. That said though, here are two links with some pretty common spam words, both of which have a good start to their list:
http://www.wilsonweb.com/wmt8/spamfilter_phrases.htm
http://spamassassin.apache.org/tests_3_1_x.html