I guess maybe I should always sleep and then try and search the next day. I found some good info for SpamAssassin and Postfix but this is out of the Zimbra context. That being said this is what I have learned in case anyone needs to do this.
Set up a spam and a ham alias (ham is a false positive). If a user gets mail marked as spam by SpamAssassin they can forward this mail to one of the aliases. With a bit of Postfix configuration you can have these emails fed back into sa_learn which is a SpamAssassin program to get it to learn better. This howto is located at
http://gtmp.org/pub/sa-postfix.en.html
I have not tested this but it looks like it will work.
Comments anyone? Us newbies need all the help we can get.