Astronomia.gr is the first attempt for the constitution of a Greek, online and free encyclopedia focusing exclusively on astronomy and space science. The cornerstones of this effort, and, at the same time the distinguishing factors from other sources of information existing in the Greek language web is the astronomical orientation that gives the advantage of a solid and margined field, and the Wiki philosophy as this has been established by wikipedia, namely the user-contributed development of the content. Astronomia.gr was founded by members of the Astronomical Society of Patras, Orion, and was released to the public in August 2006. Today, astronomia.gr numbers more than eight hundred articles about astronomy in terms of science and amateur occupation, as well as articles about astrophysics, cosmology and space science. We present explicitly the function of this work, the results so far and the tasks for further development of the project.