DataStax’ Brisk is an enhanced open-source Apache Hadoop and Hive distribution that utilizes Apache Cassandra for many of its core services. Brisk provides integrated Hadoop MapReduce, Hive and job and task tracking capabilities, while providing an HDFS-compatible storage layer powered by the Cassandra DB.
DataStax Brisk Apache Cassandra Hadoop

A key benefit of DataStax’ Brisk is the tight feedback loop it allows between real-time applications and the real time analytics that follow. Traditionally, users would be forced to move data between systems via complex ETL processes, or perform both functions on the same system with the risk of one impacting the other.

http://www.datastax.com/products/brisk

http://ria101.wordpress.com/2010/02/24/hbase-vs-cassandra-why-we-moved/

http://www.theregister.co.uk/2011/03/23/cassandra_mashed_with_hadoop/

http://allthingshadoop.com/2010/04/24/running-hadoop-mapreduce-with-cassandra-nosql/

http://pig.apache.org/

Rackspace casandra by example:
http://www.rackspace.com/cloud/blog/2010/05/12/cassandra-by-example/