Cloudera and other sides have made available a number of resources for help all of us to get up to speed with using Hadoop etc.
So if you are starting out with Hadoop here is a short list of key resources that I have found very useful.
Cloudera Hapood Virtual Machine
The Hadoop FAQ for DBAs
Cloudera Newsletter for Developers
Cloudera New to Hadoop
Udacity course : Introduction to Hadoop and MapReduce