Attain Apache Solr Coding Chops by Peter Wolanin and Chris Pliakas.
From the description:
This session is for those who are excited by the great power of Apache Solr search for Drupal but want to understand how to customize their search and use Solr to power parts of the site. Join us for a technical deep dive into the world of Apache Solr search integration focused on the expanded possibilities in Drupal 7, as well as the improving overlap between the front-end components that interface with Solr and other search back ends like the PHP Zend lucene api.
Drupal oriented but still a good review of various options for using Solr.