Maven is not present in default repositories for SL6. For many people administrating and doing development with quattor it is convenient to develop in the same platform as the machines that are managed.
Yum Repository configuration
cat /etc/yum.repos.d/maven.repo
# Note: Replaced $releasever with 6Server since SL's "6.2" doesn't work
[epel-apache-maven]
name=maven from apache foundation.
baseurl=http://repos.fedorapeople.org/repos/dchen/apache-maven/epel-6Server/$basearch/
enabled=1
skip_if_unavailable=1
gpgcheck=0
[epel-apache-maven-source]
name=maven from apache foundation. - Source
baseurl=http://repos.fedorapeople.org/repos/dchen/apache-maven/epel-6Server/SRPMS
enabled=0
skip_if_unavailable=1
gpgcheck=0
How to install
Run: yum install apache-maven
You may need to relog for maven to be added to your enviroment variables.
HTTP proxies
If you are behind proxy you need to edit /usr/lib/jvm/java-1.6.0-openjdk-1.6.0.0.x86_64/jre/lib/net.properties or its equivalent. There are some environment variables too but they did not work for me. java.net.useSystemProxies=true with http__proxy environment variable worked.