Barlaam and Ioasaph 
Each chapter in its own file, with links to previous, next, table of contents, or any other chapter. If you are using a graphical browser, this is the online equivalent of a "large print" edition.
http://www.worldwideschool.org/library/books/relg/historygeography/BarlaamandIoasaph/toc.htmlAn Exact Exposition of the Orthodox Faith 
Appears to be the same translation as at CCEL, but without notes. The benefit of this version, at St. Nicholas Orthodox Church, Dallas, is that you can jump to a particular chapter.
http://www.orthodox.net/fathers/index.html
In Defense of Icons 
Two excerpts from the writings of St. John of Damascus.
http://www.fordham.edu/halsall/source/johndam-icons.html
Saint John Damascene on Various Subjects 
Extracts from the saint's writings on topics including free will and Paradise.
http://home.it.net.au/~jgrapsas/pages/Damascus.html
Three Sermons on the Dormition of the Virgin 
Mary H. Allies translation. In HTML, with notes.
http://www.fordham.edu/halsall/basis/johndamascus-komesis.html
Apologia Against Those Who Decry Holy Images 
Mary H. Allies translation. Three parts. In HTML, with notes.
http://www.fordham.edu/halsall/basis/johndamascus-images.html
Anacreontic Hymn (Extract) 
Translated by Elizabeth Barrett Browning.
http://www.voskrese.info/spl/browning.html#damasc
Barlaam and Ioasaph 
The story of Barlaam and Ioasaph, by "John the Monk". Traditionally ascribed to St. John Damascene, but possibly actually the work of St. Euthymius the Georgian.
http://omacl.org/Barlaam/
An Exact Exposition of the Orthodox Faith 
Each of the four books in its own HTML file, with notes, at Christian Classics Ethereal Library. From A Select Library of Nicene and Post-Nicene Fathers of the Christian Church, second series, vol. 9.
http://www.ccel.org/ccel/schaff/npnf209.iii.html