Apache Mahout is a new open source project by the Apache Software Foundation (ASF) with the primary goal of creating scalable machine-learning algorithms that are free to use under the Apache license. The project is entering its second year, with one public release under its belt. Mahout contains implementations for clustering, categorization, CF, and evolutionary programming. Furthermore, where prudent, it uses the Apache Hadoop library to enable Mahout to scale effectively in the cloud.
Apache Mahout Wikipedia - http://en.wikipedia.org/wiki/Apache_Mahout
Apache Mahout Wiki - https://cwiki.apache.org/MAHOUT/mahout-wiki.html
Apache Mahout Wiki - https://cwiki.apache.org/MAHOUT/mahout-wiki.html
What is Apache Mahout - http://mahout.apache.org/
Introducing Apache Mahout - http://www.ibm.com/developerworks/java/library/j-mahout/
Introduction to Apache Mahout - http://www.slideshare.net/gsingers/intro-to-mahout-dc-hadoop
Data Mining using Mahout - http://search.iiit.ac.in/cloud/presentations/8.pdf
Apache Mahout: a formidable collection of Data mining algos on the top of Hadoop (Map Reduce) - http://codingplayground.blogspot.com/2010/08/apache-mahout-formidable-collection-of.html
Machine Learning using Mahout - http://www.slideshare.net/gsingers/intro-to-apache-mahout
IBM Hadoop and Mahout online resources - http://www.ibm.com/developerworks/java/library/j-mahout/#resources