I use outlook express, windows xp platform. I cannot find the field option to add the spam option.

Are you trying to add the spam field? That's only possible for users of the Outlook plug-in. You may want to read FAQs 2.1 and 4.21: <http://spambayes.org/faq.html#does-spambayes-work-with-outlook-express> <http://spambayes.org/faq.html#how-do-i-set-up-spambayes-and-outlook-express

=Tony.Meyer -- Please always include the list (spambayes at python.org) in your replies (reply-all), and please don't send me personal mail about SpamBayes. http://www.massey.ac.nz/~tameyer/writing/reply_all.html explains this.