Katta Lucene+hadoop
http://katta.sourceforge.net/about
Solr + Hadoop = Big Data Love
http://architects.dzone.com/articles/solr-hadoop-big-data-love
Bixo Labs http://bixolabs.com/
Hbase+Hadoop+solr =Lily
http://www.lilyproject.org/lily/index.html
SolrCloud
http://wiki.apache.org/solr/SolrCloud
Nutch
Solr
lucene+zookeeper = zoie
Riak Search
http://www.basho.com/products_lab.php
Hadoop+Solr
How Rackspace Now Uses MapReduce and Hadoop to Query Terabytes of Data
http://highscalability.com/how-rackspace-now-uses-mapreduce-and-hadoop-query-terabytes-data