Owing to the fact that a Living Reviews in Relativity article may evolve over time, we recommend to cite the article as follows:
Clifford M. Will,
"The Confrontation between General Relativity and Experiment",
Living Rev. Relativity 9, (2006), 3. URL (accessed <date>):
http://www.livingreviews.org/lrr-2006-3
The date given as <date> then uniquely identifies the version of the article you are referring to.