Hmmm, Digester doesn't seem so popular on the ol'ranch.
Here are some tutorials I have found helpful in getting my code running with my Lucene integration.
http://www.theserverside.com/articles/article.tss?l=Digester http://www-106.ibm.com/developerworks/library/j-lucene/ I have got the hang of this tool now. It is pretty handy for grabbing content from an xml to put in a Lucene document.
If anyone has questions on this or Lucene please feel free to send me a message through JavaRanch. I am no expert but I may be able to at least point you in the right direction.