M2_HOME (points to you local maven installation)

JAVA_HOME (point to your JDK 5 installation)

add %M2_HOME%/bin to your PATH environment variable

optionally you would like to override the default (M2_HOME/conf/settings.xml#//localRepository) where maven creates the local cache repository (default is ~/.m2)

if necessary add and configure the proxies section in settings.xml. This is a list of proxies which maven uses to connect to the network like the central mirror.