It functions with five main fonts:
There is one Unicode font inclued: Aristarcoj (available at http://www.russellcottrell.com/greek/fonts.asp).
You need the java-runtime version >= 1.5 (available at http://www.java.com/getjava/).
Some links about writing Greek with Unicode Fonts
You paste non-unicode Greek text in the superior pane, click on the "Convert" and copy the converted text from the read-only inferior pane.