To use XTarget, you have to download and install Java and Groovy first.
Then download the jdom-1.1.3.jar, xtarget-X.X.X.jar and xtarget-groovy-X.X.X.jar libraries here, and put them in the ~/.groovy/lib folder (Like "C:/Users/lfgr/.groovy/lib"). Then XTarget can be used in any groovy scripts (for documentation, see http://groovy.codehaus.org/).
There are no tutorials on XTarget yet. Please view the javadoc (xtarget-doc-X.X.X and xtarget-groovy-doc-X.X.X) available at the download section.